Tumours of the Liver and Intrahepatic Bile Ducts · CHAPTER 8 Tumours of the Liver and Intrahepatic...

CHAPTER 8

Tumours of the Liver and Intrahepatic Bile Ducts

The most frequent and important hepatic neoplasm is the pri-mary hepatocellular carcinoma (HCC). In many parts of theworld, in particular Africa and Asia, it poses a significant dis-ease burden. In these high incidence regions, chronic infec-tion with hepatitis B virus (HBV) is the principal underlyingcause, with the exception of Japan which has a high preva-lence of hepatitis C infection. HBV vaccination has become apowerful tool in reducing cirrhosis and HCC, but implementa-tion is still suboptimal in several high risk regions. In Westerncountries, chronic alcohol abuse is a major aetiological factor.

Hepatic cholangiocarcinoma has a different geographical dis-tribution, with peak incidences in Northern Thailand. Here, it iscaused by chronic infection with the liver fluke, OpisthorchisViverrini, which is ingested through infected raw fish.

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WHO histological classification of tumours of the liver and intrahepatic bile ducts

TNM classification1, 2, 3

T Primary TumourTX Primary tumour cannot be assessedT0 No evidence of primary tumour

T1 Solitary tumour 2 cm or less in greatest dimension without vas-cular invasion

T2 Solitary tumour 2 cm or less in greatest dimension with vascularinvasion; or multiple tumours limited to one lobe, none more than2 cm in greatest dimension without vascular invasion; or solitarytumour more than 2 cm in greatest dimension without vascular invasion.

T3 Solitary tumour more than 2 cm in greatest dimension with vas-cular invasion; or multiple tumours limited to one lobe, none morethan 2 cm in greatest dimension with vascular invasion; or multi-ple tumours limited to one lobe, any more than 2 cm in greatestdimension with or without vascular invasion.

T4 Multiple tumours in more than one lobe; or tumour(s) involve(s) amajor branch of the portal or hepatic vein(s); or tumour(s) withdirect invasion of adjacent organs other than gallbladder; ortumour(s) with perforation of visceral peritoneum.

N – Regional Lymph NodesNX Regional lymph nodes cannot be assessedN0 No regional lymph node metastasisN1 Regional lymph node metastasis

M – Distant MetastasisMX Distant metastasis cannot be assessedM0 No distant metastasisM1 Distant metastasis

Stage GroupingStage I T1 N0 M0Stage II T2 N0 M0Stage IIIA T3 N0 M0Stage IIIB T1 N1 M0

T2 N1 M0T3 N1 M0

Stage IVA T4 Any N M0Stage IVB Any T Any N M1

TNM classification of tumours of the liver and intrahepatic bile ducts

158 Tumours of the liver and intrahepatic bile ducts

Epithelial tumours

BenignHepatocellular adenoma (liver cell adenoma) 8170/01

Focal nodular hyperplasiaIntrahepatic bile duct adenoma 8160/0Intrahepatic bile duct cystadenoma 8161/0Biliary papillomatosis 8264/0

Malignant

Hepatocellular carcinoma (liver cell carcinoma) 8170/3Intrahepatic cholangiocarcinoma 8160/3

(peripheral bile duct carcinoma)Bile duct cystadenocarcinoma 8161/3Combined hepatocellular and cholangiocarcinoma 8180/3Hepatoblastoma 8970/3Undifferentiated carcinoma 8020/3

Non-epithelial tumours

Benign

Angiomyolipoma 8860/0Lymphangioma and lymphangiomatosis 9170/0Haemangioma 9120/0Infantile haemangioendothelioma 9130/0

Malignant

Epithelioid haemangioendothelioma 9133/1Angiosarcoma 9120/3Embryonal sarcoma (undifferentiated sarcoma) 8991/3Rhabdomyosarcoma 8900/3

OthersMiscellaneous Tumours

Solitary fibrous tumour 8815/0Teratoma 9080/1Yolk sac tumour (endodermal sinus tumour) 9071/3Carcinosarcoma 8980/3Kaposi sarcoma 9140/3Rhabdoid tumour 8963/3Others

Haemopoietic and lymphoid tumours

Secondary tumours

Epithelial abnormalities

Liver cell dysplasia (liver cell change)Large cell type (large cell change)Small cell type (small cell change)

Dysplastic nodules (adenomatous hyperplasia)Low-gradeHigh-grade (atypical adenomatous hyperplasia)

Bile duct abnormalitiesHyperplasia (bile duct epithelium and peribiliary glands)Dysplasia (bile duct epithelium and peribiliary glands)Intraepithelial carcinoma (carcinoma in situ) 8500/211

Miscellaneous lesions

Mesenchymal hamartomaNodular transformation

(nodular regenerative hyperplasia)Inflammatory pseudotumour

_________1 Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded

/0 for benign tumours, /1 for unspecified, borderline or uncertain behaviour, /2 for in situ carcinomas and grade III intraepithelial neoplasia and /3 for malignant tumours.

_________1 {1, 66}. This classification applies only to primary hepatocellular and cholangio-(intrahepatic bile duct) carcinomas of the liver.2 A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.3 For classification, the plane projecting between the bed of the gallbladder and the inferior vena cava divides the liver in two lobes.

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159Hepatocellular carcinoma

Hepatocellular carcinoma S. Hirohashi H.E. BlumK.G. Ishak Y. DeugnierM. Kojiro P. Laurent PuigI.R. Wanless H.P. FischerN.D. Theise M. SakamotoH. Tsukuma

Fig. 8.01 Worldwide annual incidence (per 100,000) of liver cancer in males(1995). Numbers on the map indicate regional average values.

DefinitionA malignant tumour derived from hepato-cytes. Most common aetiological factorsare viral infections (HBV, HCV), dietaryaflatoxin B1 ingestion and chronic alco-hol abuse.

EpidemiologyPrimary liver cancer (PLC) is a majorpublic health problem worldwide. In1990, the global number of new caseswas estimated at 316,300 for males and121,100 for females, accounting for 7.4%(males) and 3.2% (females) of all malig-nancies, excluding skin cancer {1469}.Hepatocellular carcinoma (HCC) is themost common histological type of PLC.Population-based cancer registries showthat HCC as a percentage of histologi-cally specified PLCs varies considerably{1471} but in over half of the registries,the fraction is above 70%. Regions with percentages less than 40%are exceptional, e.g., Khon Kaen (Thai-land), where intrahepatic cholangiocarci-noma is predominant, due to endemicinfection with liver flukes (Opisthorchisviverrini) {1470}. Owing to the limitedavailability of histological data, the follow-ing epidemiological survey is based onPLC but it can be assumed that it largelyreflects HCC incidence and mortality.

Geographical distributionThe estimated PLC incidence in 1990 for23 areas of the world is shown in Figure8.01 {1469}. High-risk areas with an age-standardized incidence rate (ASIR, stan-dardized to world population) of morethan 20.1 per 100,000 for males are Sub-Saharan and South Africa, East Asia,and Melanesia. Low-risk areas with anASR < 3.2 are North and South America,South-Central Asia, Northern Europe,Australia and New Zealand. Thus, devel-oping countries carry the greatest dis-ease burden, with more than 80% ofaccounted global cases. The geograph-ical distribution of PLC is similar formales and females, although males havea considerably higher risk of developingPLC. Geographical variations in PLC riskare present even in relatively homoge-nous populations and environments{1471, 176}. Geographical variations in HCC inci-dence and mortality can be ascribed todifferent levels of exposure to HCC riskfactors: chronic infections with hepa-titis B virus (HBV) and aflatoxin expo-sure in developing countries, and smok-ing and alcohol abuse in developedcountries {1545, 1482, 1417}. In Japan,local differences in the age-standardizedmortality rate (ASMR, standardized to

world population) reflect the sero-preva-lence of anti-hepatitis C virus (anti-HCV)antibodies among blood donors {1973,1893, 1471, 67}.

Time trendsIn most countries, the incidence ratesstayed largely constant or have de-creased over the past two decades.However, they have increased in Japanand Italy, especially for males {982,1522}. A changing prevalence of risk fac-tors among populations as well aschanges in diagnostic techniques and inclassification of the disease and appre-ciably affected the disease incidence.

Fig. 8.02 Geographic distribution of the prevalence of chronic HBV infection,based on HBs Ag serology.

Fig. 8.03 Age-specific incidence rates of liver can-cer in males for selected populations 1992. From: M. Parkin et al. {1471}.

> 8% = high2-7% = intermediate< 2% = low

3.6

6.6 35.8

28.4

3.14.1

< 3.6 < 5.4 < 10.8 < 20.9 < 48.9

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Age and sex distributionRegional age-specific incidence ratesdiffer significantly (Fig. 8.03). Qidongand Hong Kong (China) are high-riskpopulations for HBV-related HCC.Characteristics of their curves are asteep increase in the ages 20-34 years;in Qidong the curve levels off already atthe age of 40. Osaka (Japan) is a high-risk area, but Varese (Italy) is a low tointermediate risk area; approximately70% of HCC in these populations is relat-ed to chronic HCV infection {1417}. Theirrates increase at older ages and showrelatively high rates over age 55-59. Thecurve for whites in the USA (SEER data)is representative of both low-risk popula-tions. Males are always more frequentlyaffected than females but high male tofemale ratios of > 3 in the age-specificrates occur particularly in populationswith a high incidence of HCC {1534, 402,1906, 391, 452}.

AetiologyChronic infection with HBV, HCV or bothis the most common cause of HCCworldwide {889}. Among Western popu-lations, alcohol-induced liver injury is aleading cause of liver cirrhosis and con-stitutes the most important HCC risk{426}. In Southern China and sub-Saharan Africa, dietary ingestion of highlevels of aflatoxin may present a specialenvironmental hazard, particularly in indi-viduals chronically infected with HBV.Other exogenous factors have also beenincriminated, including iron overload{1155}, long-term use of oral contracep-tives {1158, 2034}, and high-dose ana-bolic steroids. The development of livercirrhosis, particularly in association withinherited genetic diseases such asalpha-1-antitrypsin deficiency or haemo-chromatosis, place the individual at agreatly increased risk of HCC develop-ment.HCC risk is increased if aetiological riskfactors exist in combination, e.g., HCVinfection and alcohol use {341} or HBVinfection and exposure to aflatoxin{1864}.

Liver cirrhosisThe major clinical HCC risk factor is livercirrhosis, largely independent of its aeti-ology (Fig. 8.04). Approximately 70–90%of HCCs develop in patients withmacronodular cirrhosis which is charac-terised by the presence of large nodules

of varying size (up to several centimetersin diameter), containing portal fields andefferent veins, separated by broad, irreg-ularly shaped connective tissue septaeand scars. Macronodular and mixedmacro-micro-nodular cirrhosis are typi-cally caused by or associated with viralhepatitis, metabolic disorders, and toxicliver injury. Micronodular cirrhosis ischaracterised by uniform nodules ofapproximately 3 mm that lack the typicalliver architecture and do not contain acentral vein. They are typically observedas a consequence of alcoholic liver dis-ease, haemochromatosis, and biliary cir-rhosis.

Hepatitis B virus (HBV) HBV is a small DNA virus belonging tothe group of hepatotropic DNA virusesknown as hepadnaviruses. HBV consistsof an outer envelope, composed mainlyof hepatitis B surface antigen (HBsAg),and an internal core (nucleocapsid),which contains hepatitis B core antigen(HBcAg), a DNA polymerase/reversetranscriptase, and the viral genome. Thegenome consists of a partly double-stranded circular DNA molecule of about3200 base pairs with known sequenceand genetic organisation. In recentyears, HBV variants with mutations inviral genes and in some regulatorygenetic elements have been detected inpatients with HBV infection; these muta-tions can have biological consequences.Epidemiological studies have convinc-ingly shown that HCC development isclosely associated with chronic HBVinfection. The incidence of HCC in chron-

ically HBV-infected individuals is approx-imately 100 times higher than in the unin-fected population, and the lifetime HCCrisk of males infected at birth approach-es 50%. In the absence of a commonmolecular mechanism for HBV-inducedhepatocarcinogenesis, definitive prooffor a direct oncogenic role of HBV is stilllacking. Nevertheless, at least three linesof evidence support a direct oncogenicrole for HBV in the development of HCC:(1) integration of HBV DNA into the chro-mosomal DNA of HCCs, (2) the role ofthe HBV X gene in the pathogenesis ofHBV-associated HCCs, in particular itsbinding to and inactivation of p53, and(3) HCC development in animal modelsof chronic hepadnavirus infection. Inaddition, the declining HCC incidencefollowing HBV vaccination clearly sup-ports the aetiological contribution {275).Chronic hepatitis D virus (HDV) infectiondoes not increase the risk of HCC devel-opment over that of HBV infection alone,but the latency period between HDVinfection and HCC development is 30-40

Fig. 8.04 Overview of outcome of HBV infection.

Infection

Symptomaticacute hepatitis B

Asymptomaticacute hepatitis B

Fulminant hepatitis

Cirrhosis

Chronic infection

Death

Hepatocellular carcinoma

(Death)

(Death)

“Healthy” carrier

Fig. 8.05 Interactions between aflatoxin B1 (AFB1)and HBV infection in liver cancer.

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years, compared with 30-60 years forHBV infection alone.

Hepatitis C virus (HCV)HCV has a single-stranded RNA genomeof positive polarity, around 10 kb inlength, that codes for a single polypro-tein consisting of 3010-3033 aminoacids. Post-translational processing inthe 5'-3' direction yields the structuralprotein C (RNA-binding nucleocapsidprotein) and the E1 and E2 envelope pro-teins, and the non-structural proteinsNS1-NS5, including RNA-dependentRNA polymerase {321}.As soon as the HCV genome was cloned,it became evident that viruses isolatedfrom various geographic regions havemarked genetic heterogeneity. Sequencecomparison shows at least 6 differentHCV genotypes. Although mutationshave been identified in all regions of theHCV genome, the genes for the envelopeproteins E1 and E2 appear to be particu-larly variable. A mutation rate of 1 or 2nucleotides per 1000 bases per infection-year appears to be characteristic ofchronic HCV infection. This mutation rateis about 10 times higher than that of HBV.Some HCV genotypes may be more fre-quently associated with HCC develop-ment than others {321}.Anti-HCV antibodies are found in15–80% of HCC patients, depending onthe patient population studied. HCVappears to be a major cause of HCC inJapan, Italy, and Spain, but it seems toplay a less important role in South Africaand Taiwan {321}. HCV-associated HCCstypically develop after 20-30 years ofinfection and are generally preceded byliver cirrhosis. Thus far, there is no evi-dence to suggest that HCV integratesinto the cellular genome or has anotherdirect role in the molecular pathogenesisof HCC. Rather, HCC develops via HCV-induced chronic liver injury, progressingto fibrosis and cirrhosis.

AlcoholAmong Western populations, alcohol-induced liver injury is the leading causeof chronic liver disease and liver cirrhosisand constitutes the most important HCCrisk factor {426}. Regular daily consump-tion of > 50g ethanol in females or > 80g in males is generally consideredsufficient to induce liver cirrhosis,although individual susceptibility canvary considerably. Patients who abuse

alcohol and have coexisting liver diseasefrom other causes (such as chronic HCVinfection) have the highest risk for HCCdevelopment {341, 1432, 1508, 2106}.

Aflatoxin B1 (AFB1)AFB1 is a potent liver carcinogen in sev-eral animal species as well as in humans{2128}. It is produced by the mouldsAspergillus parasiticus and Aspergillusflavus which under hot and humid condi-tions in tropical countries typically con-taminate grain, particularly ground nuts

(peanuts). Dietary ingestion of high lev-els of aflatoxins presents a significantenvironmental hazard, particularly in thecontext of coexisting chronic HBV infec-tion {1864, 1265} which leads to a morethan 50-fold increase in the risk of devel-oping HCC (Fig. 8.05).AFB1 is metabolized by cytochromeP450 enzymes to its reactive form,AFB1-5,9-oxide, which covalently bindsto cellular macromolecules. Reactionwith DNA at the N7 position of guaninepreferentially causes a G:C > T:A muta-

Fig. 8.06 Hepatocellular carcinoma. A Nodular type. B Massive type. C Diffuse type. D Multifocal type.

Fig. 8.07 Hepatocellular carcinoma, trabecular.

A B

C D

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tion in codon 249 of the TP53 tumoursuppressor gene, leading to an aminoacid substitution of arginine to serine{188}. In Southern China andSubsaharan Africa, the two world regionswith the highest levels of food contami-nation with AFB1, this mutation is presentin > 40% of HCC {1265} and can bedetected in serum DNA of patients withpreneoplastic lesions and HCC {924}. Inregions where AFB1 levels in food arevery low or undetectable, codon 249transversion mutations are either veryrare or absent.

Clinical featuresSymptoms and signsMost HCC patients have a past or currenthistory of chronic liver disease from dif-ferent causes {1681}. The major clinicalrisk factor for HCC development is livercirrhosis; 70–90% of HCCs develop in amacronodular cirrhosis {452}.The presenting symptoms in patientswith HCC include abdominal pain, gen-

eral malaise, anorexia or weight loss, andnausea or vomiting. The symptoms arecaused by the underlying chronic liverdisease or cirrhosis and its clinical com-plications, or by the HCC itself. The mostcommon clinical signs in HCC patientsare hepatomegaly, ascites, fever, jaun-dice, and splenomegaly. The laboratory findings are in part deter-mined by the underlying liver disease,which results in elevations of various liverenzymes, such as aspartate amino trans-ferase (AST), alanine aminotransferase(ALT), alkaline phosphatase (AP),gamma-glutamyl-transpeptidase (GGT),and bilirubin. These laboratory parame-ters are not HCC-specific, however. Asignificantly raised level of alpha-fetopro-tein (AFP) of > 500 ng/ml, or continuous-ly rising values even if less than 100ng/ml, strongly suggest HCC. However,not all cases of HCC are associated withAFP elevation, and raised AFP may alsobe found in liver disease without HCC.Furthermore, in the early stages of HCC

development, AFP levels do not closelycorrelate with clinical HCC stage. AFPlevels, therefore, have to be interpretedindividually in the context of other clinicalsymptoms and signs as well as imagingstudies. Another HCC-specific marker isdes-gamma-carboxyprothrombin (DCP),which is roughly equivalent to AFP. Occasionally, HCC patients develop aparaneoplastic syndrome, with erythrocy-tosis, hypoglycaemia or hypercalcaemia.

ImagingImaging studies are important in patientmanagement for the identification andlocalization of HCC. Useful techniquesinclude ultrasonography of the liver andthe abdomen, colour Doppler ultra-sonography, computed tomography(CT), lipiodol CT, magnetic resonanceimaging, angiography, and possiblypositron emission tomography. The stan-dard imaging techniques are ultrasonog-raphy and CT. In most cases, these allowHCC detection and staging. In patients

Fig. 8.08 Histological subtypes of hepatocellular carcinoma. A Pseudoglandular. B Clear cell. C Fatty change. D Spindle cell. E Scirrhous type. F Scirrhous type,Masson trichrome stain. G Poorly differentiated, with numerous mitotic figures. H Pleomorphic. I Multinucleated giant cell.

A B C

D E F

H G I

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with suspected HCC metastases, a chestX-ray, bone scan, or other imagingmodalities may be indicated.

Liver biopsyThe definitive diagnosis of HCC dependson the histological examination of thelesion, especially in AFP-negativepatients. Ultrasound- or CT-guided percu-taneous biopsy with a 22-gauge needleusually provides sufficient tissue for diag-nosis with minimum risk of bleeding orseeding of tumour cells along the needletract. However, in patients with signifi-cantly elevated AFP levels who are poten-tially eligible for HCC resection or livertransplantation, liver biopsy is not recom-mended to eliminate the residual risk oftumour cells spreading before surgery.

MacroscopyMacroscopic features of HCCs varydepending on the size of the tumour andthe presence or absence of liver cirrho-sis. In general, most HCCs associated

with liver cirrhosis tend to present as anexpansile tumour with a fibrous capsuleand intratumoural septa, while thosewithout cirrhosis tend to be massive andnon-encapsulated. Varying degrees ofinfiltrative growth, tumour thrombi in theportal veins, and intrahepatic metas-tases, which are common in advancedtumours, modify the gross appearance.Occasionally, numerous minute tumour

nodules are distributed throughout theliver and may be difficult to be distin-guished from regenerative nodules inliver cirrhosis.Hepatocellular carcinomas are occasion-ally pedunculated. Patients are usuallyfemales and the tumours are thought toarise in accessory lobes of the liver.Following surgical resection, the progno-sis is excellent.

Hepatocyte (Dako)Polyclonal carcinoembryonic antigenAlpha fetoproteinFibrinogenCytokeratins 8 and 18Cytokeratins 7 and 19Cytokeratin 20Epithelial membrane antigenBER EP4

Positive (most useful in diagnosis) Positive (canalicular pattern)Positive or negativePositive or negativeUsually positiveUsually negativeUsually negativeNegativeNegative

Antigen Result

Table 8.01Immunohistochemistry of HCC.

Fig. 8.10 Pale bodies in hepatocellular carcinoma. A Haematoxylin and eosin. B Immunoreactivity for fibrinogen.

Fig. 8.09 A Numerous Mallory bodies in a hepatocellular carcinoma (two examples indicated by arrows). B Hyaline inclusions in a hepatocellular carcinoma.A B

A B

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Tumour spreadInvasion into the blood vessels, in partic-ular into the portal vein, is a characteris-tic of HCC. Tumour thrombi in the portalveins are present in more than 70% ofautopsies of advanced HCCs. Intra-hepatic metastases is caused mostly bytumour spread through the portal veinbranches. Tumour invasion into the majorbile ducts is infrequent clinically, butfound in about 6% of autopsy cases.Extrahepatic metastasis is mostlyhaematogenous, the lungs being themost common target. Regional lymphaticmetastasis is frequent though distantlymph nodes are rarely involved.

HistopathologyHCCs consist of tumour cells that resem-ble hepatocytes. The stroma is com-posed of sinusoid-like blood spaces linedby a single layer of endothelial cells.Unlike the sinusoidal endothelial cells innormal liver tissue, those of HCC areimmunohistochemically positive for CD34 and factor-VIII-related antigen.Ultrastructural observation shows a base-ment-membrane-like structure betweenthe endothelial cells and tumour cell tra-beculae, and basement-membrane-likematerials are immunohistochemicallypositive with antibodies for laminin andtype IV collagen. Thus, the sinusoid-likeblood spaces resemble capillary vessels.This phenotypic change of sinusoids iscalled 'capillarization' {472, 919, 917}. In the sinusoidal blood spaces, varyingnumbers of macrophages, which showimmunohistochemical positivity with anti-lysozyme and CD68, are also presentand resemble Kupffer cells in well differ-

entiated tumours {1894}. HCCs varyarchitecturally and cytologically. The dif-ferent architectural patterns and cytolog-ical variants frequently occur in combina-tion. Immunohistochemical features ofHCC are summarized in Table 8.01.

Architectural patternsTrabecular (plate-like). This pattern is themost common in well and moderately dif-ferentiated HCCs. Tumour cells grow incords of variable thickness that are sep-arated by sinusoid-like blood spaces.Well-differentiated tumours have a thintrabecular pattern and trabeculaebecome thicker with de-differentiation.Sinusoid-like blood spaces often showvarying degrees of dilatation, and pelio-sis hepatis-like change are occasionallyobserved in advanced HCCs. Pseudoglandular and acinar. HCC fre-quently has a glandular pattern, usuallyadmixed with the trabecular pattern. Theglandular structure is formed mostly by asingle layer of tumour cells, and someglandular or acinar structures are formedby dilatation of the bile canaliculus-likestructure between cancer cells. Pseudo-glands frequently contain proteinaceousfluids, which often stain with PAS but donot stain with mucicarmine or Alcian blue.Bile may be present. Cystic dilatation ofthe pseudoglands sometimes occurs,such dilated glands are occasionallyformed by degeneration of thick trabecu-lae. Generally, the glandular structure issmaller in well differentiated tumours thanin moderately differentiated tumours. Compact. Sinusoid-like blood spacesare inconspicuous and slit-like, givingthe tumour a solid appearance.

Scirrhous. This uncommon type is char-acterised by marked fibrosis along thesinusoid-like blood spaces with varyingdegrees of atrophy of tumour trabeculae.It is observed even in small tumours. Thescirrhous type should not be confusedwith cholangiocarcinoma or fibrolamellarcarcinoma. Similar fibrotic changesoccur following chemotherapy, radiation,and transchemo arterial embolization.Such post-therapeutic fibrosis should bedistinguished from the scirrhous variant.The term 'sclerosing hepatic carcinoma'

Fig. 8.12 Immunostaining for polyclonal CEAdemonstrates canaliculi in a hepatocellular carci-noma.

Fig. 8.13 Bile production in a hepatocellular carci-noma.

Fig. 8.11 Hepatocellular carcinoma in a 17-year old patient with Fanconi anaemia. A Green bile staining and extensive necrosis and haemorrhage. B Trabecular andpseudoglandular pattern with bile plugs.

A B

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{1424}, which has been used to desig-nate a variety of tumours arising in non-cirrhotic livers and associated withhypercalcemia, does not constitute a dis-tinct histopathological entity {806}, someof these tumours appear to be hepato-cellular, but others are intrahepatic(peripheral) cholangiocarcinomas.

Cytological variantsPleomorphic cell. Tumour cells showmarked variation in cellular and nuclearsize, shape, and staining. Bizarremultinucleated or mononuclear giantcells are often present, and osteoclast-like giant cells may be seen rarely.Generally, pleomorphic tumour cells lackcohesiveness and do not show a distincttrabecular pattern. Pleomorphic cells arecommon in poorly differentiated tumours.Clear cell. The tumour consists predom-inantly of cells with clear cytoplasm dueto the presence of abundant glycogen.This type is sometimes difficult to distin-guish from metastatic renal cell carcino-ma of clear cell type.Sarcomatous change. HCC occasionallyappears sarcomatous, characterised bythe proliferation of spindle cells or bizarregiant cells. When the tumour consistssolely of sarcomatous cells, it is difficultto distinguish from sarcomas such asfibrosarcoma and myogenic sarcoma.When sarcomatous features are predom-inant, the tumour is called sarcomatoidHCC or sarcomatous HCC. In manycases, however, the sarcomatouschange is present in a part of the tumour,and transitional features betweentrabecular HCC and sarcomatous com-ponents are frequent. Sarcomatouschange is more frequent in cases withrepeated chemo-therapy or transchemoarterial embolization {953}, but it is alsoseen in small tumours. Most sarcoma-tous cells are positive for vimentin ordesmin but negative for albumin and

alpha-fetoprotein. Some are also positivefor cytokeratin.Fatty change. Diffuse fatty change ismost frequent in small, early-stagetumours less than 2 cm in diameter. Itsfrequency declines as tumour sizeincreases, and fatty changes are ratherinfrequent in advanced tumours. Meta-bolic disorders related to hepatocarcino-genesis and insufficient blood supply inthe early neoplastic stage have beensuggested as a possible mechanism forthe development of fatty change in smalltumours, but a definite mechanism hasnot yet been determined.Bile production. Bile is occasionallyobserved, usually as plugs in dilatedcanaliculi or pseudoglands. When bileproduction is prominent, the tumour isyellowish in color and turns green afterformalin fixation.Mallory hyaline bodies are intracytoplas-mic, irregular in shape, eosinophilic andPAS-negative. They consist of aggregat-ed intermediate filaments and showimmunohistochemical positivity with anti-ubiquitin antibodies. Globular hyaline bodies are small, round,homogeneous, and strongly acidophilicintracytoplasmic bodies. They arePAS-positive and stain orange to red withMasson trichrome stain. Immunohisto-chemically, they are often positive foralpha-1-antitrypsin.Pale bodies are intracytoplasmic, roundto ovoid, amorphous and lightly eosino-philic. They represent an accumulationof amorphous materials in cysticallydilated endoplasmic reticulum, andshow distinct immunohistochemical pos-itivity with anti-fibrinogen {1846}. Theyare commonly seen in the fibrolamellarvariant of HCC but are also found in thecommon types of HCC, especially inscirrhous HCC.Ground glass inclusions are rarelyobserved in tumours of HBsAg-positive

patients. They stain with modified orcein,Victoria blue, or aldehyde fuchsin, andshow immunohistochemical positivitywith anti-HBsAg antibody. They are notseen in tumour casts in the portal vein orin extrahepatic metastases, and most arethought to be HBsAg-positive hepato-cytes entrapped in a tumour.

Fibrolamellar HCCThis variant usually arises in non-cirrhoticlivers of adolescents or young adults{353}. It is rare in Asian and African coun-tries but not so rare in Western countries.The tumour cells grow in sheets or smalltrabeculae that are separated by hyalin-ized collagen bundles with a character-istic lamellar pattern. They are large andpolygonal and have a deeply eosino-philic and coarsely granular cytoplasmand distinct nucleoli. The eosinophilicgranularity is due to the presence of alarge number of mitochondria. Pale bod-ies are frequently present, and stainablecopper, usually in association with bile,can occasionally be shown.

Undifferentiated carcinoma Undifferentiated carcinoma is rare,accounting for less than 2% of epithelialliver tumours. There is male preponder-ance but data on geographical distribu-tion are not available. Localization, clini-cal features, symptoms and signs, anddiagnostic procedures display no differ-ence as compared to hepatocellular car-cinoma. Undifferentiated carcinomas arepostulated to have a worse prognosis(compared to HCC), although greatercase numbers to support this are notavailable {351, 806}.

GradingAccording to histological grade, HCC isclassified into well differentiated, moder-ately differentiated, poorly differentiated,and undifferentiated types.

Fig. 8.14 Nodule-in-nodule type of hepatocellular carcinoma. The border between early and advanced components is shown in C.A B C

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Well differentiated HCC. This is mostcommonly seen in small, early-stagetumours less than 2 cm in diameter andis rare in advanced tumours. The lesionsare composed of cells with minimal atyp-ia and increased nuclear/cytoplasmicratio in a thin trabecular pattern, with fre-quent pseudoglandular or acinar struc-tures and frequent fatty change. In mosttumours larger than 3 cm in diameter,well-differentiated carcinoma is observedonly in the periphery if at all.Moderately differentiated HCC. The mod-erately differentiated type is the common-est in tumours larger than 3 cm in diame-ter and is characterized by tumour cellsarranged in trabeculae of three or morecells in thickness. Tumour cells have

abundant eosinophilic cytoplasm andround nuclei with distinct nucleoli. Apseudoglandular pattern is also frequent,and pseudoglands frequently containbile or proteinaceous fluid.Poorly differentiated HCC. This prolifer-ates in a solid pattern without distinctsinusoid-like blood spaces, and only -slitlike blood vessels are observed inlarge tumour nests. Neoplastic cellsshow an increased nuclear/cytoplasmicratio and frequent pleomorphism, includ-ing bizarre giant cells. Poorly differentiat-ed HCC is extremely rare in small early-stage tumours.Malignant progression of HCC. HCC isknown to vary histologically even within asingle nodule. From the viewpoint of his-tological grade, most cancer nodulesless than 1 cm in diameter have a uniformdistribution of well differentiated cancer-ous tissues, whereas approximately 40%of cancer nodules 1.0-3.0 cm in diameterconsist of more than 2 types of tissue ofdifferent histological grades {900}. Lessdifferentiated tissues are always locatedinside, surrounded by well differentiatedtumour on the outside. The area of welldifferentiated neoplasm diminishes as thetumour size increases, and they are com-pletely replaced by less-well-differentiat-ed cancerous tissues when the tumoursize reaches a diameter of around 3 cm.When less-well-differentiated areas withina well differentiated tumour nodule aregrowing expansively, the nodule oftenhas a 'nodule-in-nodule' appearance{1275}.

Multicentric development of HCCHCCs frequently occur as multiple intra-hepatic nodules. Genetic analysis of

HBV integration pattern, chromosomalallele loss, and mutational inactivation oftumour suppressor genes has indicatedmulticentric independent development ofthese nodules {1647, 1392}. These stud-ies have shown that nodules apparentlygrowing from portal vein tumour thrombior satellite nodules surrounding a largemain tumour represent intrahepaticmetastases, whereas other nodules canbe considered multicentric HCCs if theysatisfy any of the following three criteria:(1) multiple, small early-stage HCCs orconcurrent small early-stage HCCs andclassical HCCs; (2) presence of periph-eral areas of well differentiated HCC inboth lesions or in the smaller ones; and(3) multiple HCCs of obviously differenthistology. Multicentric HCCs are associated with ahigh rate of tumour recurrence, evenafter curative resection, making treat-ment difficult and the prognosis poor.The presence of hyperplastic foci, small-cell dysplasia, an increase in the prolifer-ative activity of non-tumourous liver tis-sue, or the progression of backgroundliver disease are risk factors for multicen-tric HCC development {1902, 1859}.


Fig. 8.15 A, B Fibrolamellar type of hepatocellular carcinoma.

Fig. 8.17 Adenomatous hyperplasia with minimalnuclear atypia and without features of malignancy.

Fig. 8.16 Early hepatocellular carcinoma showingwell differentiated histological features.

A B

A

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Precursor and benign lesionsEarly stage HCC and precancerouslesionsBecause of remarkable advances inimaging techniques and their wide-spread availability, increased numbers ofsmall HCCs are detected clinically. Livertransplantation has become commontreatment for liver cirrhosis and HCC inhighly selected cases. Studies of resect-ed and explant livers have revealed newinformation about the morphologicalcharacteristics of small early-stage HCCand equivocal nodular lesions. The moststriking information is that HCC associat-ed with cirrhosis probably evolves fromprecancerous lesions, and well differenti-ated HCC further progresses to a lessdifferentiated form {952, 1646, 1882,1645, 81}.

Histological features of small early-stageHCCAlthough some small HCCs show fea-tures of classical HCCs, most less than1.5 cm in diameter are vaguely nodularwith indistinct margins macroscopicallyand have a uniform distribution of welldifferentiated cancerous tissues. Theyare characterized by increased cell den-sity with increased nuclear/cytoplasmicratio, increased staining intensity(eosinophilic or basophilic), irregular thintrabecular pattern with a frequent acinaror pseudoglandular pattern, and fattychange {959, 1324}. Diffuse fatty changeof tumour cells is present in approxi-mately 40% of tumours less than 2 cm indiameter. Many portal tracts are presentwithin the tumour nodule, and tumour cellinvasion into some portal tracts can beseen. At the tumour boundary, neoplastic

cells proliferate as though they arereplacing normal hepatocytes ('replacinggrowth'), and there is no capsule forma-tion. These small tumours may corre-spond to 'carcinoma in-situ' or 'microin-vasive carcinoma' of the liver. They tendto preserve the underlying liver struc-tures, including portal tracts, receive por-tal blood supply, and do not show tumourblushing in angiographic examinations.In contrast, classical HCCs, even if smalland well differentiated, show tumourblushing without portal flow {1883}.Invasion into the stromal tissue can besometimes identified, but vascular inva-sion and intrahepatic metastases areexceptional {1942}. Moreover, theselesions are locally curable, have a favor-able long-term outcome, and can bedefined clinically as 'early HCC'.

Adenomatous hyperplasia (dysplasticnodules)This lesion is characterized by markedenlargement of individual cirrhotic nod-ules that show thick liver cell plates.Small nodular lesions, most of which arebelow 1.5 cm in size, have been noticedin the livers of patients with HCCs thathave been resected surgically and inexplant cirrhotic livers. The nodules showvariable atypia but lack features of defi-nite malignancy. Macroscopically, mostlesions are vaguely nodular and are notmuch different from small, well differenti-ated HCC with indistinct margins; it isalmost impossible to distinguish themfrom cancer on the one hand or fromlarge regenerative nodules on the otherhand. Microscopically, they are charac-terized by a moderate increase in celldensity with a slightly irregular trabecular

pattern. There are many portal tractswithin the nodules but no invasion intothe portal tracts. These nodules some-times contain distinct, well differentiatedcancer foci. Many of them gave rise todistinct HCC in clinical follow-up studies{1882, 1645} and are, therefore, consid-ered precancerous lesions. Some of

Fig. 8.19 A–C Atypical adenomatous hyperplasiawith mild atypia and extensive fatty change.

Fig. 8.18 Adenoma. A Extensive central haemorrhage. B Benign appearing hepatocytes arranged in plates, one or two cells thick.

1 cm

A B

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these nodules contain areas with amarked increase in cell density, a moreirregular trabecular pattern, and frequentfatty change, characteristic of well differ-entiated HCC but insufficient in extent towarrant such a diagnosis. These foci have been designated adeno-matous hyperplasia {1080, 806} or dys-plastic nodule {64}. Additional termsused for these lesions include macrore-generative nodule, hyperplastic noduleand borderline lesions. Morphological criteria for the differentialdiagnosis of adenomatous hyperplasia(dysplastic nodule, low grade), atypicaladenomatous hyperplasia (dysplastic

nodule, high grade) and early-stageHCC are still under discussion, mainlydue to the lack of objective phenotypic orgenotypic markers {1080, 64, 805}.

Focal liver cell dysplasia (LCD) Large cell dysplasia. The term liver celldysplasia (LCD) was first coined byAnthony et al. {73} to describe a changecharacterized by cellular enlargement,nuclear pleomorphism and multinucle-ation of liver cells occurring in groups oroccupying whole cirrhotic nodules. Thechange was found in only 1% of patientswith normal livers, in 7% of patients withcirrhosis and in 65% of patients with cir-rhosis and HCC. There was a strong rela-tionship between LCD and HBsAgseropositivity {73}. They concluded thatthe presence of LCD identified a group ofpatients at high risk for development ofHCC, and that such patients should befollowed by serial alpha-fetoproteindeterminations.Small cell dysplasia. Watanabe et al.{2068} have expanded the original defi-nition of LCD to include a 'small cell' vari-ant. The nuclear/cytoplasmic ratio isincreased in small cell dysplasia, theratio being between that of liver cancerand normal hepatocytes. This is in con-trast to large cell dysplasia that has nor-mal nuclear/cytoplasmic ratio. Also,multinucleation and large nucleoli arecharacteristic of large cell dysplasia butnot small cell dysplasia. The small dys-plastic cells have more of a tendency toform small round foci than large dysplas-tic cells. On the basis of their morpho-logical and morphometric studiesWatanabe et al. {2068} proposed the

hypothesis that small cell dysplasia,rather than large cell dysplasia, is theprecancerous lesion in man.

Hepatocellular adenomaA benign tumour composed of cellsclosely resembling normal hepatocytes,which are arranged in plates separatedby sinusoids. On gross examination,adenomas are soft, rounded, yellow ortan masses, often with areas of necrosis,haemorrhage, and fibrosis. A fibrouscapsule is uncommon. Lesions are soli-tary in two-thirds of cases {511}. Whenmore than 10 lesions are encountered, adiagnosis of 'adenomatosis' has beenrecommended {511}. Adenoma is histologically composed ofbenign-appearing hepatocytes arrangedin plates one or two cells in thickness{64, 803, 351, 71}. Portal tracts areabsent; the lesion is supplied by arteriesand veins. In most cases, the tumourcells are uniform in size and shape, butoccasionally, mild to moderate cytologi-cal variation may be seen. Mitotic activi-ty is almost never found. Lipofuscin, fatand clear cell change (due to water orglycogen accumulation) are often pres-ent in the cytoplasm. Haemorrhage,infarction, fibrosis, and peliosis hepatismay be seen.The differential diagnosis may be difficultwith small biopsies. Features suggestinghepatocellular carcinoma include mito-ses, high nuclear/cytoplasmic ratio, andplates more than 2 cells in thickness.Loss of a normal reticulin pattern is com-mon in HCC whereas it is preserved inhepatocellular adenoma. HCC typicallyalso shows diffuse capillarization using

Fig. 8.20 Focal nodular hyperplasia. A Solitary lobulated nodule with typical central stellate scar. B Masson trichrome stain shows extensive blue connective tissuecomponent.

Fig. 8.21 Nodular regenerative hyperplasia.A Multiple pale nodules of varying size. B Reticulinstain showing mild distortion of liver architecture.

A B

A

B

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CD34 immunostain in comparison withhepatocellular adenoma, which is eithernegative or shows only focal staining.Any evidence of ductular differentiationsuggests a regenerative lesion such asfocal nodular hyperplasia (FNH). Portaltracts within the peripheral portion of anadenoma may cause confusion.The clinical setting is an important con-sideration in differential diagnosis. Mostpatients have a known risk factor, espe-cially the use of contraceptive or anabol-ic steroids. Glycogen storage diseasehas also been associated. A diagnosis ofadenoma should be made with caution inthe absence of a known cause or in thepresence of cirrhosis, where dysplasticnodules, carcinoma, and large regenera-tive nodules are far more frequent.

Focal nodular hyperplasia (FNH) A lesion composed of hyperplastic hepa-tic parenchyma, subdivided into nodulesby fibrous septa which may form stellatescars. The majority of FNH lesions areasymptomatic. Infarction may lead toabdominal pain but rupture is rare. Whenmore than one FNH lesion is present thepatient often has other features suggest-ing a systemic abnormality of angiogen-esis, including hepatic haemangioma,intra-cranial lesions (vascular malforma-tions, meningeoma, astrocytoma), anddysplasia of large muscular arteries{2054, 2055}.Most FNH lesions are solitary, firm, andlobulated nodules (Fig. 8.20). Lesions onthe surface of the liver may protrudeabove the capsule. On cut section, theyare circumscribed but not encapsulated,and paler than the surrounding liver.They typically consist of a central stellatescar surrounded by parenchymalnodules. Although most lesions are palerthan the surrounding liver, a lesscommon telangiectatic type has promi-nent blood-filled vascular spaces {64,2055}.Histologically, FNH has a regular hierar-chical structure defined by the arterialsupply, which is usually a single arterywith several orders of branching. Eachterminal branch is located in the centerof a 1 mm nodule. The large arteriesoften have degenerative changes in themedia and eccentric intimal fibrosis. Thearteries are found in a fibrous stromawithout portal veins and usually withoutducts. Proliferating ductules are usuallypresent and may be prominent, com-

monly with visible features of chroniccholestasis (cholate stasis, copper accu-mulation) and neutrophil infiltration.Nascent FNH is a small region of hyper-plasia or dilated sinusoids, recognised inthe context of more definite FNH lesions.The rare telangiectatic type of FNH has asimilar arterial supply but with markedlydilated sinusoids comprising at least aquarter of the lesion.The histological differential diagnosis ofFNH includes cirrhosis, in which septacontain portal areas, and hepatocellularadenoma. If the ductular component isnot sampled, an unequivocal diagnosismay not be possible.

Nodular regenerative hyperplasia (NRH) This condition is characterized by smallregenerative nodules dispersed through-out the liver, associated with acinar atro-phy with occlusive portal vascularlesions.The liver has a normal weight and shapewith a fine granularity of the capsular sur-face. The cut surface demonstrates a dif-fuse nodularity with most nodules meas-uring 1-2 mm. Occasionally, there areclusters of nodules up to several cm indiameter {64, 2056, 2053}. The nodulesare paler than the atrophic hepaticparenchyma which surrounds them. Microscopically, the normal architectureis mildly distorted by widespread atrophyadmixed with numerous monoacinarregenerative nodules. The nodules arecomposed of normal-appearing hepato-cytes in plates 1-2 cells wide centered

on portal tracts. The atrophic regionshave small hepatocytes in thin trabecu-lae with dilated sinusoids. No significantparen-chymal fibrosis is present butnumerous small portal veins are obliter-ated.Histological diagnosis of NRH dependson the recognition of a nodular architec-ture in the absence of parenchymalfibrosis. Nodularity may be suspectedwhen there are two adjacent populationsof hepatocytes that are normal andatrophic, respectively. This pattern isbest appreciated on a reticulin stain.Macro-nodular, incomplete septal, orregressed cirrhosis commonly haveregions with this configuration, especial-ly in livers with healed portal vein throm-bosis {1742}. These forms of cirrhosisare difficult to exclude in a small biopsy.

Genetic susceptibilitySeveral rare inherited disorders ofmetabolism are associated with anincreased risk of developing HCC.

Carbohydrate metabolism disordersIn glycogen storage disease (GSD),especially type 1 {323}, HCC can devel-op within preexisting adenomatouslesions {137}. Distinction betweenbenign and malignant tumours is difficult,since GSD-associated HCCs are well dif-ferentiated, and atypical lesions ('nodulewithin nodule' pattern and Mallory bod-ies) are found commonly in GSD-relatedadenomas {137, 1527}. Cirrhosis is neverpresent.

Fig. 8.22 Multicentric, independent development of two HCC (T1 and T2), indicated by differences in theirHBV DNA integration pattern. (N, normal tissue)

(kb)23.19.46.6

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HindIII BamHI

T1 T2 N T1 T2 N

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Protein metabolism disordersIn alpha-1-antitrypsin deficiency (A1ATD){1501}, only male A1ATD homozygotesare at high risk for HCC, even in theabsence of cirrhosis {473}. Further-more,cholangiocarcinomas and combinedhepatocellular and cholangiocarcinomasin non-cirrhotic livers of adult patientswith heterozygous A1ATD of PiZ type arewell documented {2207}. HCC occurs in18%-35% of patients with hereditarytyrosinaemia {2082, 1996}. The non-tumourous liver is cirrhotic and often dys-plastic {808}. HCC has further beenreported in 14% of adult-onset cases ofhypercitrullinaemia in the absence of cir-rhosis {1324A}.

Disorders of porphyrin metabolism. Theprevalence of HCC in porphyria cutaneatarda (PCT) ranges from 7% to 47%{1755, 1073}. Almost all HCCs occur inmale patients older than 50 years withpreexisting cirrhosis and a long-standinghistory of symptomatic PCT. The involve-ment of additional risk factors is likely{396}. Rarely, PCT evolves as a para-neoplastic syndrome associated withHCC {1389}. Other hepatic porphyrias

are occasionally associated with HCC{1073, 53}.

Chronic cholestatic syndromes. HCC may complicate paucity of intra-hepatic bile ducts {1028, 99, 898},biliary atresia {2082}, congenital hepaticfibrosis {2082}, and Byler syndrome{1550}.

Metal-storage diseases.The relative risk for the development ofprimary liver cancer in inheritedhaemochromatosis has been calculatedas being greater than 200 {181, 1351,487}. HCC develops usually in patientswith cirrhosis {403, 951}, even after irondepletion {403}. Iron-free foci (defined asclear-cut, sublobular, hepatocytic nod-ules free of iron or having significantlyless iron than the surrounding parenchy-ma) may represent an early step of HCCin genetic haemochromatosis {403}. InWilson’s disease, HCC is present onlyexceptionally {293}.

Hepatic vascular anomalies. Cases of HCC have been occasionallyreported in hereditary haemorrhagic

telangiectasia {831} and ataxia-telang-iectasia {2083}.

Extrahepatic inherited conditions. Several cases of HCC have been report-ed in familial adenomatous polyposis ofthe colon {1000}. Occasional cases havealso been described in neurofibromato-sis, Soto syndrome, and situs inversus{2082}. Cases of hepatocellular adeno-mas and HCC in young patients withFanconi anaemia have been alsodescribed {1033}.

GeneticsClonal expansion and subclonal progres-sion during multistage carcinogenesisMost HCCs are associated with HBV orHCV infection. Clonal expansion of hepa-tocytes is initiated during regeneration indamaged livers; a clonal integration pat-tern of HBV was identified in cirrhoticnodules {2170}. Advanced HCCs oftenemerge as ‘nodule-in-nodule’ HCCs; theearly and advanced HCC components ofa ‘nodule-in-nodule’ type HCC showedidentical integration patterns of HBV{1968, 1647}. Ordinary HCCs with in-creased cell proliferation and neovascu-larization are subsequently formed.

TP53 mutationsPoint and frameshift mutations of theTP53 tumour suppressor gene are fre-quent in areas with low exposure to afla-toxin B1 {1393}. TP53 mutations weremost frequent and were clustered indomains IV and V in poorly differentiatedHCCs, but were less frequent and equal-ly distributed in domains II to V in well ormoderately differentiated HCCs in onestudy {1393}. Analysis of ‘nodule-in-nod-ule’ type HCC shows that TP53 mutationis associated with the progression ofHCC from an early to a more advancedstage {1392, 1391}.In areas with high exposure to AFB1,mutation of the third nucleotide in codon249 of TP53 is frequent {758, 188}, sug-gesting that some TP53 mutations can befingerprints of past exposure to a givencarcinogen (see 'Aetiology', above).

HBV XThe HBV X open reading frame is fre-quently integrated and expressed. HBVX [MLS1] can bind to the C terminus ofp53, inhibits its sequence-specific DNAbinding and transcriptional activationand suppresses p53-induced apoptosis

Fig. 8.23 CpG methylation around E-cadherin promoter in HCCs and non-tumorous liver showing chronichepatitis or cirrhosis. CpG methylation was detected in 46% of liver tissues showing chronic hepatitis or cir-rhosis and 67% of HCCs. Heterogenous E-cadherin expression was detected in hepatocytes in 7 (41%) of the17 liver tissues showing chronic hepatitis or cirrhosis; small focal areas of hepatocytes showed only slightE-cadherin immunoreactivity. Reduced E-cadherin expression was observed in 10 (59%), in which over 50%of the HCC cells in each patient lacked or showed only slight E-cadherin immunoreactivity, of the 17 HCCs.

Chronic hepatitis HCC HCC

C1 C2 H99N H99T H103N H103T

EB EBM

EBH

EB EBM

EBH

EBM

EBH

EBM

EBH

EBM

EBH

EBM

EBH

E, EcoRI; B; BamHI; M, Mspl; H, Hpall; C1 and 2, cases with liver metastatic lesionsof primary colonic cancer; H99 and 103, HCC cases.

= normal liver tissue = cirrhotic liver tissue = HCC

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{2050, 2051, 457}. HBV X may affect awide range of p53 functions and therebycontribute to the molecular pathogenesisof HCCs. HBV X further inhibits nucleo-tide excision repair {858}.

OncogenesMutational activation of known onco-genes is rare. Point mutations of the c-KRAS gene and coamplification of thecyclin D1 gene were detected in only 3%{1967} and 11% {1355} of HCCs, respec-tively.Recent findings, obtained by compara-tive genomic hybridization of amplifiedsequences mapped to 11q12, 12p11,and 14q12, may lead to the characteri-zation of new genes involved in hepato-carcinogenesis {1163}.

Wnt pathway and beta-cateninIn the wingless/Wnt pathway, mutationsof the β-catenin gene were detected in26-41% of HCCs {386, 760}. Nuclearaccumulation of β-catenin was observedby immunohistochemistry in all HCCswith β-catenin mutations {760}. No muta-tion was detected in mutation clusterregion of the APC gene in any of 22HCCs analysed {760}. Deletions on chro-mosomes 1p, 4q, and 16p weresignificantly associated with the absenceof β-catenin mutation, which suggeststhat a β-catenin-activating mutation isinvolved in cases without chromosomalinstability {1041}.

Genetic instability and allelic loss Frequent allelic losses have been foundat loci on 1p, 4q, 5q, 8p, 11p, 13q, 16p,16q, and 17p by restriction fragmentlength polymorphism analysis {2046,200, 1970, 2203, 546, 1759, 459, 460}.Loss of heterozygosity (LOH) on chromo-some 16 was detected in 52% of inform-ative cases {1970}. The common deletedregion lay between HP (16q22.1) andCTRB (16q22.3-q23.3) loci {1970}.These losses occurred more frequentlyin HCCs with poor differentiation, of largesize, and with metastasis, and were notdetected in early-stage HCCs {1970}.LOH on chromosome 16 may beinvolved in enhancement of tumouraggressiveness. Recent development ofmicrosatellite markers allows an exten-sive allelotypic analysis {2171, 163,1307, 1515, 659, 108}. Detailed deletionmapping revealed that allelic loss at a 1-cM-interval flanked by D4S2921 and

D4S2930 loci on 4q35 was frequent inHCCs with poor differentiation and oflarge size {108}. Inactivation of unidenti-fied tumour suppressor genes within thisregion may contribute to progression ofHCCs.Microsatellite instability is another path-way for genetic instability other thanchromosomal instability. Only 11% ofHCCs had replication errors in one study,and the incidence of replication errorscorrelated significantly with poor differ-entiation and portal vein involvement ofHCCs {961}.

Cell cycle regulatorsThe gene product of p16INK4 binds tocyclin-dependent kinase (CDK) 4 andprevents CDK4 from forming an activecomplex with cyclin D. p16 protein lossmay contribute to both early- and late-stage hepatocarcinogenesis, because it

was observed in 22% of early-stageHCCs and occurred approximately twiceas often in advanced HCCs as in early-stage HCCs {763}. Neither p16 homozy-gous deletion/mutation nor loss of p16mRNA expression was observed inHCCs lacking p16 protein {763}, sug-gesting post-transcriptional inactivation.DNA methylation around the promoterregion of the p16 gene has beenobserved in HCC {1187}.Expression of p21WAF1/CIP1 mRNA, auniversal CDK inhibitor, was reducedmarkedly in 38% of HCCs {762}. p21mRNA expression of HCCs with TP53mutations was significantly lower thanthat of HCCs with wild-type TP533 {762}.p21 expression is regulated predomi-nantly by dependence on TP53 in HCCs.mRNA expression of p27Kip1, another uni-versal CDK inhibitor, was reduced in52% of HCCs {764}.

Fig. 8.24 Correlation between TP53 mutation at codon 249, dietary exposure to aflatoxin B1, and regional inci-dence of hepatocellular carcinoma (HCC).

Senegal (10/15)

Mozambique (8/15)

China (Quidong, Quanxi; 38/73)

Thailand (1/15) Japan (1/274)

Sth. Africa (Transkei, Natal; 3/48)

China (Shanghai; 3/52)

Europe/USA (0/107)

Prevalence of TP53 mutation (codon 249; AGG > AGT); % of total HCC

Average range of aflatoxinB1 intake (ng/kg body weightper day)

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40

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Fig. 8.25 DNA sequencing autoradiographs of β-catenin mutations in HCC {760}.

Fig. 8.26 Nuclear accumulation of β-catenin proteinin neoplastic hepatocytes in a HCC associated withHCV infection {760}.

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Growth factorsTransforming growth factor-beta (TGF-β)was expressed at a high level in 82% ofHCCs and was associated with HBVinfection {756}. TGF-β expression couldbe part of a chain of events by which HBVcontributes to the development of HCCs.TGF-β1, TGF-β2, and TGF-β3 showedmarked mRNA overexpression in HCCs{818, 12}. TGF-β was expressed in bothtumour and stroma cells; this suggeststhat TGF-β may play a role in hepatocar-cinogenesis through both autocrine andparacrine pathways {12}. The mannose-6-phosphate / insulin-like growth factor-IIreceptor (M6P/IGF2R) regulates cell pro-liferation through interactions with TGF-βand IGF II. A study from the U.S.A. report-ed LOH at the M6P/IGF2R locus andmutations of the remaining allele wereidentified in 61% and 55% of HCCs,respectively {2149}, while no M6P/IGF2Rmutations were detected in HCCs fromJapanese patients {2031}. Angiogenic growth factors. mRNAexpression of basic fibroblast growth fac-tor (bFGF) was high in HCCs {1746}.Strong immunoreactivity for bFGF was

localised in the progressed HCC compo-nent but not in the early-stage compo-nent of a nodule-in-nodule HCC {712}.Acquisition by cancer cells of the capac-ity to produce bFGF could be an impor-tant event in the stepwise progression ofHCC. Greater mRNA expression of vas-cular endothelial growth factor (VEGF)was found in 60% of HCCs and was sig-nificantly correlated with the intensity oftumour staining in angio-grams. Thissuggests that VEGF contributes signifi-cantly to angiogenesis during hepatocar-cinogenesis {1239, 1869}.

DNA methylationDNA methyltransferase (DNMT1) mRNAexpression was significantly higher inchronic hepatitis and cirrhotic nodulesthan in normal livers, and was even high-er in HCCs {1863}. Indeed, DNA hyper-methylation at D16S32, TAT, and D16S7loci on chromosome 16 is frequentlypresent even in chronic hepatitis and cir-rhotic nodules {885}. The incidence anddegree of aberrant DNA methylationincreased in HCCs compared withchronic hepatitis and cirrhotic nodules

{885}. Aberrant DNA methylation mayparticipate even in the early develop-mental stages of HCCs by predisposingsome loci to allelic loss or silencing spe-cific genes {885}.DNA methylation around the promoterregion of the E-cadherin tumour suppres-sor gene, which is located on 16q22.1,was detected in 46% of chronic hepatitisand cirrhotic nodules and in 67% ofHCCs {884}. DNA hypermethylationaround the promoter region correlatedsignificantly with reduced E-cadherinexpression in HCCs {884}. The HIC-1(hypermethylated-in-cancer) tumour sup-pressor gene was identified at the D17S5locus. DNA hypermethylation at theD17S5 locus was detected in 44% ofchronic hepatitis and cirrhotic nodulesand in 90% of HCCs {883}. LOH at thislocus, which was preceded by DNAhypermethylation, was detected in 54%of HCCs {883}. The HIC-1 mRNA expres-sion level of chronic hepatitis and cirrhot-ic nodules was significantly lower thanthat of normal livers, and that of HCCswas even lower {883}. Thus, silencing oftumour suppressor genes by aberrantDNA methylation is a significant eventduring hepatocarcinogenesis.

Prognosis and predictive factorsThe prognosis of patients with HCC isgenerally very poor, particularly in caseswith AFP levels greater than 100 ng/ml atthe time of diagnosis, partial or completeportal vein thrombosis, and presence ofa TP53 mutation {45, 1861}. Sponta-neous regression has been reportedrarely. Most studies report a five-year sur-vival rate of less than 5% in symptomaticHCC patients. HCCs are largely resistantto radio- and chemotherapy. Long-termsurvival is likely only in patients withsmall, asymptomatic HCC that can betreated by surgical resection, includingliver transplantation, or non-surgicalmethods, including percutaneous etha-nol or acetic acid injection and percuta-neous radiofrequency thermal ablation.

Fig. 8.27 Malignant progression in a HCC (T1) with new tumour clones (T2, T3). Only T3 shows a mutation inTP53. Macroscopy shows typical ‘nodule-in-nodule’ pattern. Neo-angiogenesis (arrow) is restricted to oneof the nodules.

TP53 mutationsPCR-SSCP

analysis

Angiogenesis

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173Intrahepatic cholangiocarcinoma

DefinitionAn intrahepatic malignant tumour com-posed of cells resembling those of bileducts. Intrahepatic (or peripheral) cholan-giocarcinoma (ICC) arises from any por-tion of the intrahepatic bile duct epitheli-um, i.e. from intrahepatic large bile ducts(the segmental and area ducts and theirfiner branches) or intrahepatic small bileducts. Cholangiocarcinoma arising fromthe right and left hepatic ducts at or neartheir junction is called hilar cholangiocar-cinoma and is considered an extrahepat-ic lesion.

EpidemiologyIncidence and geographical distributionICC is a relatively rare tumour in mostpopulations but second among primarymalignant liver tumours; about 15% ofliver cancers are estimated to be ICC{61, 2162, 1467}. The frequency of ICCamong all liver cancers ranges from 5%in males and 12% in females in Osaka,Japan, to 90% in males and 94% infemales in Khon Kaen, Thailand {1467,1471} (Fig. 8.29).The highest incidence of ICC is found inareas of Laos and North and NortheastThailand suffering from endemic infec-tion with the liver fluke, Opisthorchisviverrini. In 1997, the age standardizedincidence of ICC in Khon Kaen(Thailand) was 88 per 100,000 in malesand 37/105 in females {1467, 1471}.About 90% of the histologically con-firmed cases of liver cancer in KhonKaen are ICC, and almost all the ICCcases were found to be related tochronic O. viverrini infection {2006,2007}. In the Clonorchis sinensis endem-ic area in Korea, there is also a highincidence of liver cancer with truncateincidence rates (35-64 years group) of75 per 100,000 in males and 16 per100,000 in females {23}. About 20%of liver cancers in Pusan, Korea, areICC {871}.

Time trendsIn both endemic and non-endemicareas, there have been no significant

changes in the incidence of ICC in recentyears {61}. It is less than 10 years sinceO. viverrini drug therapy was initiated;since it probably takes 30 years for ICCto complicate opisthorchiasis, the trendsof ICC are probably not likely to changein the next decade {2007, 2009}.

Age and sex distributionPatients with ICC are elderly, with noclear sex differences. ICC occurs atrather older ages than hepatocellularcarcinoma (HCC) in most clinical series{1419}.

AetiologyAlthough many aetiological factors havebeen characterized, the cause of ICCremains speculative in many cases.

ParasitesClonorchis sinensis parasitizes the bileducts of millions of individuals in the FarEast, particularly China and Korea

{1467}. Early reports from Hong Konghave shown that 65% of patients withICC were infected by C. sinensis {747}.However, the incidence of C. sinensisinfection in the general population wasalso similarly high at that time {308}. ICCfrom this cause appears to less frequentin recent years.By contrast, infection of O. viverrini iscontinuing in Northeast Thailand, and

Y. Nakanuma A.S.-Y LeongB. Sripa T. PonchonV. Vatanasapt K.G. Ishak

Intrahepatic cholangiocarcinoma

Fig. 8.28 Histology of the liver fluke, Opisthorchisviverrini, in a hepatic bile duct.

0 10 20 30 40 85 95

Thailand, Khon KaenJapan, Osaka

Hong KongJapan, Hiroshima

Singapore, ChinesePhilippines, Manila

Thailand, Chiang MaiSingapore, Malay

Italy, VareseFrance, Bas-Rhin

Switzerland, ZurichSpain (6 registries)

FinlandUSA, SEER, Black

DenmarkSlovakiaScotland

Israel, JewsCanada

USA, SEER, WhiteNew Zealand, non Maori

Australia (4 states)

= CCA

= HCC

= All

CCA

84.62.85.41.01.01.46.11.90.91.00.40.51.20.61.10.80.70.30.40.40.40.2

HCC

6.837.927.924.624.218.211.311.58.67.85.14.12.93.32.11.91.72.21.81.61.31.7

All

94.241.639.228.527.223.519.714.310.69.16.05.84.74.24.02.92.92.82.52.42.12.0

Fig. 8.29 Age-standardized incidence of liver cancer, per 100,000, in males, 1992 . Rates for cholangiocarci-noma and hepatocellular carcinoma are estimates. From: M. Parkin et al. {1468}

8a 19.7.2006 8:14 3


the evidence for the role of opisthorchia-sis in the induction of ICC is compelling{2009, 2008}. Carcinogenesis is proba-bly related to the length and severity ofinfection, the host’s immune response,and other variables such as ingestion ofdietary carcinogens, for example nitro-samines. In northeast Thailand, severalcarcinogenic N-nitroso compounds andtheir precursors exist at low levels in thedaily diet {1230}. In addition, endo-genous nitrosamine formation by liverfluke infection has been reported {1673}.Both exogeneous and in situ nitrosamineformation may lead to DNA alkylationand deamination {1346}. It seems thatthe presence of parasites induces DNAdamage and mutations as a conse-quence of the formation of carcino-gens/free radicals and of cellular prolif-eration of the intrahepatic bile ductepithelium.

HepatolithiasisHepatolithiasis (recurrent pyogeniccholangitis), which is not uncommon inthe Far East, is also associated with ICC{1857, 1321}. It is frequently observed inclonorchiasis {746} but not in opisthor-chiasis. Most of these cases are associ-ated with calcium bilirubinate stones; afew cases with cholesterol stones havealso been reported. Patients with intra-hepatic stones and ICC have a signifi-cantly longer duration of symptoms anda higher frequency of previous biliarysurgery.

Inflammatory bowel disease and primarysclerosing cholangitisPatients with primary sclerosing cholan-gitis (PSC) and ulcerative colitis (UC)have a predisposition to develop col-orectal neoplasia and also bile ductcarcinoma, including ICC {672, 1993,194, 2078}.

Epstein-Barr virus (EBV) infectionRare examples of ICC have a lymphoep-itheliomatous, undifferentiated pattern.Clonal EBV has been found in suchcases {757, 2025}.

Non-biliary cirrhosisThere are several reports of ICC arising innon-biliary cirrhosis, particularly hepatitisvirus-related liver cirrhosis {2159, 1940}.HCV is frequent in such cases and ICC isusually of a smaller, mass-forming type.Such ICC and combined hepatocellular-cholangiocarcinomas share apomucinprofiles {1669}, suggesting that these twotumours have a similar or common histo-genesis, or that ICC associated with cir-rhosis might be the result of exclusiveproliferation of the cholangiocellular com-ponent of the combined type. Genotypesof hepatitis B and C viruses have beenshown in cholangiocarcinoma cells{2049, 1787}.

Deposition of ThorotrastThorotrast is a radioactive α-particleemitter that was widely used as a radio-opaque intra-arterial contrast mediumbetween 1930 and 1955. ICC has beenrecorded in many patients with priorexposure to Thorotrast. The data suggestthat the chronic alpha-irradiation may bethe causative factor, with latent periodsranging from 25 to 48 years.

Biliary malformations and other lesionsICC may arise rarely in solitary unilocularor multiple liver cysts, congenital seg-mental or multiple dilatation of the bileducts (Caroli disease), congenital hepat-ic fibrosis, and von Meyenburg complex-es {736, 2165}.

Clinical featuresThe site of the tumour, its growth patternand the presence or absence of stricture

or obstruction of the biliary tree areresponsible for the variable clinical fea-tures of ICC.

Symptoms and signsGeneral malaise, mild abdominal painand weight loss are frequent clinicalsymptoms. When the carcinoma infil-trates the hilar region, jaundice andcholangitis become manifest. ICCs, par-ticularly those arising from the small bileducts, may go unnoticed until they have attained a large size. The liver isenlarged to a lesser extent, ascites is less common, and signs of portalhypertension are absent or minimal.Patients with unrelieved obstruction ofthe intrahepatic large bile ducts may diefrom complications, e.g. liver failure orsepsis.

Imaging Advanced cases of ICC show mixedgrowth and spreading patterns withintrahepatic metastases. Computerizedtomography (CT) images of ICC usuallyshow a lobulated or fused hypodensespace-occupying lesion with peripheralenhancement, probably due to centralhypocellular dense fibrosis. Secondarydilated ducts around the tumour aredetectable by CT and ultrasonography. Afocal area of carcinoma involving the bileduct wall is identifiable by spiral CT.Endoscopic retrograde, transhepatic ormagnetic resonance cholangiography isa useful adjunct for the identification ofthe level of biliary obstruction and sec-ondary bile duct dilatation.ICCs at relatively early and surgicallyresectable stages are classifiable intothree representative types of growth pat-terns {1080}, and these patterns, whichare evaluable by imaging studies, can beuseful for the preoperative staging of

Fig. 8.30 Ultrasonography of an intrahepaticcholangiocarcinoma. A hyperechoic mass is pres-ent in a dilated bile duct.

Fig. 8.31 Cholangiocarcinoma, CT images. A The right lobe contains a mass and shows peripheral bile ductdilation. B Arrows indicate a peribiliary spreading type.

A B

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tumour extent and for designing the sur-gical procedure. The mass forming typeis an expansile nodule and is the mostcommon. The tumour borders betweenthe cancerous and noncancerous por-tions are relatively clear. The contrastenhanced CT scan shows a low-density tumour with peripheral ring-likeincreased density. The periductal-infiltrat-ing type, which is usually associated withbiliary stricture, is relatively common. Thetumour exhibits diffuse infiltration alongthe portal pedicle. This type resembleshilar or extrahepatic bile duct carcinoma.The contrast enhanced CT demonstratesa small cancerous enlargement of theportal pedicle, or a mass central to thedilated peripheral ducts. The anatomicallocation of the involved ducts can beevaluated by caliber changes or therigidity of the bile duct on high-qualitycholangiographic images. The intraduc-tal growth type (intraductal papillarycholangiocarcinoma) is less common{351}. These tumours are confined withinthe dilated part of an intrahepatic largebile duct, with no or mild extension

beyond the bile duct walls. Sometumours of this type of ICC might havearisen from biliary papillomatosis aftermalignant transformation. Marked local-ized dilatation of the affected duct isdetectable by ultrasound or CT. Cholan-giography shows filling defects in the bil-iary tract, due to polypoid tumours andmucin.

MacroscopyICC can arise from any portion of theintrahepatic bile duct epithelium {61,1418}. Lesions are gray to gray-white,firm and solid, although some tumoursshow intraductal growth, sometimes withpolyp formation. Typical tumours consistof variably sized nodules, usually coales-cent. Portal tract infiltration is also seen.Central necrosis or scarring are common,and mucin may be visible on the cut sur-faces. ICC cases involving the hepatichilum are hardly distinguishable from hilarcholangiocarcinoma, and such casesshow cholestasis, biliary fibrosis, andcholangitis with abscess formation. ICCis not often noted in a non-cirrhotic liver.

ICC in endemic areas of liver fluke infec-tion is similar to that described in non-endemic regions; liver flukes are rarelyseen nowadays due to mass treatment.In hepatolithiasis-associated ICC, thetumour tends to proliferate and spreadalong the stone-containing ducts. Theliver lobe or segments containing stonesinvolved by ICC are atrophic in somecases.

Tumour spreadICC shows direct spread into the sur-rounding hepatic parenchyma, portalpedicle and bile duct. Intrahepaticmetastases develop in nearly all cases ata relatively advanced stage.Vascular invasion is a frequent histologi-cal finding relatively early, suggesting thedevelopment of early metastasis. Theincidence of metastases in regionallymph nodes is higher than in HCC.Blood-borne spread occurs later, to thelungs in particular; other sites includebone, adrenals, kidneys, spleen, andpancreas.


Fig. 8.32 Macroscopic features of intrahepatic cholangiocarcinoma. A Cut surface shows massive tumour and multiple intrahepatic metastatic nodules.Surrounding liver is non-cirrhotic. B White, scar-like mass in a normal liver (mass forming types) together with dilated peripheral bile ducts. C Intraductal growthtype of intrahepatic cholangiocarcinoma.

Fig. 8.33 Intrahepatic cholangiocarcinoma. A Well differentiated tubular adenocarcinoma. B Moderately differentiated tubular adenocarcinoma.

A B C

A B

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On rare occasions, the tumour showsextensive intraluminal spread of bileducts throughout the liver. The tumourcells can also infiltrate into the peribiliaryglands of the intrahepatic large bileducts and their conduits. It may be diffi-cult to distinguish this lesion from reac-tive proliferated peribiliary glands histo-logically.

HistopathologyMost ICCs are adenocarcinomas show-ing tubular and/or papillary structureswith a variable fibrous stroma {326}.There is no dominant histological type ofICC in cases associated with liver flukesor hepatolithiasis when compared tothose in non-endemic areas.

AdenocarcinomaThis common type of ICC growing in thehepatic parenchyma and portal pediclereveals a significant heterogeneity of his-tological features and degree of differen-tiation. At an early stage, a tubular pat-tern with a relatively uniform histologicalpicture is frequent. Cord-like or micro-papillary patterns are also seen. Thecells are small or large, cuboidal orcolumnar, and can be pleomorphic. Thenucleus is small and the nucleolus isusually less prominent than that of HCC.The majority of cells have a pale,eosinophilic or vacuolated cytoplasm;sometimes, the cells have a clear andabundant cytoplasm or resemble gobletcells.

ICC arising from the large intrahepaticbile ducts shows intraductal micropapil-lary carcinoma and in situ like spreadalong the biliary lumen. Once there isinvasion through the periductal tissue,the lesion may be well, moderately, orpoorly differentiated adenocarcinoma,with considerable desmoplasia andstenosis or obliteration of the bile ductlumen.Infrequently, a papillary tumour growingin the duct lumen is supported by finefibrovascular cores. Cholangio-carcino-ma arising from the intrahepatic peribil-iary glands {1914} mainly involves theseglands, sparing the lining epithelial cellsat an early stage.An abundant fibrous stroma is an impor-tant characteristic of ICC. Activatedperisinusoidal cells (myofibroblasts) areincorporated into the tumour, producingextracellular matrix proteins that lead tofibrosis {1913}. Usually, the central partsof the tumour are more sclerotic andhypocellular, while the peripheral partsshow more actively proliferating carcino-ma cells. On rare occasions, the tumourcells are lost in a massive hyaline stroma,which may be focally calcified.The secretion of mucus in one form oranother can be demonstrated in themajority of tumours by mucicarmine, dia-stase-PAS and Alcian blue staining.Mucus core (MUC) proteins 1, 2, and 3are detectable in the carcinoma cells{1264, 1670}. ICC cells can immunoex-press cytokeratins 7 and 19, CEA, epithe-lial membrane antigen, and blood groupantigens. Bile may be present occasion-ally in ICC as a result of destruction of thebile ducts or entrapment of non-neoplas-

Fig. 8.34 A Intrahepatic cholangiocarcinoma showing papillary growth pattern involving the peribiliary glands . The bile duct lumen (top and center) is free of car-cinoma. B Papillary cholangiocarcinoma invading the bile duct wall.

Fig. 8.35 High-grade intraepithelial neoplasia of a peribiliary gland in a patient with hepatolithiasis.

A B

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tic hepatocytes or bile ductules contain-ing bile. It is always seen at the peripheryof the tumour. Bile production by tumourcells is never found.Carcinoma cell nests with small tubularor cord-like patterns extend by com-pressing the hepatocytes or infiltratingalong the sinusoids. Occasionally, carci-noma cells abut directly on to hepato-cytes. As a result, the portal tracts areincorporated within the tumour andappear as tracts of elastic fibre-rich con-nective tissue. Fibrous encapsulation isnot seen. ICC frequently infiltrates portal tracts, andinvades portal vessels (lymphatics, portalvenules); there is also perineural inva-sion, particularly in the large portal tracts. Infiltrating, well-differentiated tubular car-cinoma must be differentiated from thenon-neoplastic pre-existing small bileducts. The carcinoma cells infiltratearound nerve fibres and have variably-sized cancerous lumens.

Adenosquamous and squamous carcino-ma. The former is an adenocarcinomacontaining significant amounts of unequi-vocal squamous carcinomatous ele-ments, i.e. keratin and/or intercellularbridges. The latter is entirely composed ofsquamous cell carcinoma. They are occa-sionally seen at advanced stages of ICC.Cholangiolocellular carcinoma. The car-cinoma cells are arranged as small, regu-lar, narrow tubular structures resemblingductules or canals of Hering {1828}. Thecells are larger than the usual ICC.Mucinous carcinoma. A predominantcomponent of extracellular mucus(mucus lakes), usually visible to thenaked eye, is present in the stroma.Carcinoma cells distended with mucusare seen floating in the mucus lakes. Thehistology is similar to that seen in otherorgans. These tumours show rapid pro-gression clinically {1671}. Signet-ring cell carcinoma. A malignanttumour in which there is a predominanceof discrete cells distended with mucus.ICC composed only of signet ring cells isextremely rare. Sarcomatous ICC. A cholangiocarcino-ma with spindle cell areas resemblingspindle cell sarcoma or fibrosarcoma orwith features of malignant fibrous histio-cytoma. This variant may have a moreaggressive behaviour. Carcinomatousfoci, including squamous cell carcinoma,are scattered focally.

Lymphoepithelioma-like carcinoma. Twocases of undifferentiated lymphoepithe-liomatous lesions with adenocarcinomahave been reported {757, 2025}. In thesecases, EBV-coded nuclear RNAs weredemonstrable.Clear cell variant. This lesion is charac-terized by distinct overgrowth of clearcells in an acinar or tubular pattern. Thetumour cells are PAS reactive and dia-stase resistant, indicating the presenceof mucin.

Mucoepidermoid carcinoma. This variantresembles the tumour arising in salivaryglands.

Differential diagnosis

Hepatocellular carcinoma. Some ICCsgrow in a cord-like pattern reminiscent ofthe trabeculae of HCC. The cords arealways separated by a connective tissuestroma rather than by sinusoids; canali-culi and bile are also absent. Almost all

Fig. 8.36 Intrahepatic cholangiocarcinoma. A Clear cell type. B Mucinous type. C Pleomorphic type. DSpindle cell type.

Fig. 8.37 Intrahepatic cholangiocarcinoma. In situ hybridisation for human telomerase mRNA shows signalin carcinoma cells (left). Non-neoplastic bile duct is negative (right).

A B

C D

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ICCs are diffusely positive for cytokeratin7 and 19, whereas only a few cases ofHCC are positive. The hepatocyte anti-gen (Dako) is expressed by HCC but notby ICC.Metastatic carcinoma. ICC cannot bedistinguished histologically from meta-static adenocarcinoma of biliary tract orpancreatic origin. Occasionally, dysplas-tic changes in neighbouring bile ductssuggest intrahepatic origin. In addition,diffuse expression of cytokeratin 20favours metastatic adenocarcinoma, par-ticularly from colon {1141}. While cyto-keratin 7 is common in ICC, it is not socommon in metastatic carcinoma.Sclerosing cholangitis. Periductalspread of ICC may be difficult to distin-guish from sclerosing cholangitis, partic-ularly when only biopsy material isavailable. The most important criteria forthe diagnosis of malignancy are severecytological atypia, random and diffuseinfiltration of the duct wall by theneoplastic cells, and perineural invasion.

GradingICCs can be graded into well, moderate-ly, and poorly differentiated adenocarci-noma according to their morphology. Inthe case of the common type of adeno-carcinoma, well-differentiated lesionsform relatively uniform tubular or papil-lary structures, moderately differentiatedtumours show moderately distorted tubu-lar patterns with cribriform formationsand/or a cord-like pattern, while the poor-ly differentiated show severely distortedtubular structures with marked cellularpleomorphism.

Precursor and benign lesions Biliary intraepithelial neoplasia (dysplasia)This is characterized by abnormalepithelial cells with multilayering of nucleiand micropapillary projections into theduct lumen {2078, 1322}. The abnormalcells have an increased nuclear/cyto-plasmic ratio, a partial loss of nuclearpolarity, and nuclear hyperchromasia.They are divisible into low-grade andhigh-grade lesions. Some peribiliaryglands may also be dysplastic. Cell kinetic studies have disclosed prolif-erative activity of intraepithelial neoplasiabetween that of hyperplasia and ICC,and telomerase activity is demonstrablein both intraepithelial and invasive carci-noma {1915, 1440}. Carcinoembryonicantigen (CEA) is focally detectable in bil-iary intraepithelial neoplasia and more soin carcinoma {1322}. These findings sup-port the concept of a hyperplasia-dys-plasia-carcinoma sequence in the biliarytree {1989}.In liver fluke infestations, the bile ductsfirst show desquamation of the epithelial

lining with subsequent hyperplasia,periductal fibrosis, inflammation andgoblet cell metaplasia {2008, 913}. Theneoplastic transformation from hyperpla-sia in bile ducts to ICC through dysplas-tic changes is demonstrable in opisthor-chiasis. In hepatolithiasis, the findingsare those of cholangitis, with proliferationof the biliary epithelial lining and peri-biliary glandular cells, and multiple fociof biliary intraepithelial neoplasia {1323}. Hyperplasia and intraepithelial neoplasiaof the duct epithelium in livers withThorotrast-deposition and congenital bil-iary anomalies may be also related to thedevelopment of ICC {1626, 2165}. It has been reported in patients with PSCthat biliary intraepithelial neoplasia couldevolve from papillary hyperplasia {2078,1107}. However, recent experience atorthotopic liver transplantation of PSChas detected hardly any in situ or inva-sive neoplastic foci.

Biliary papillomatosisDilated intrahepatic and extrahepatic bileducts are filled with papillary or villousexcrescences, which microscopically arepapillary or villous adenomas with deli-cate fibrovascular stalks covered with acolumnar or glandular epithelium {806,351}. They are soft and white, red or tan.In some cases, there are variable degreesof cellular atypia and multilayering ofnuclei. Occasionally, foci of in situ or inva-sive carcinoma are encountered {1340}.

Von Meyenburg complex (biliary micro-hamartoma) The lesions are small, up to several mmin diameter. They are usually multiple and

Fig. 8.38 Intrahepatic cholangiocarcinoma, in a patient with heterozygous alpha-1 antitrypsin deficiency of the Piz type. A Tubular adenocarcinoma. B Cytokeratin 7immunohistochemistry demonstrates tumour cells spreading along bile ducts and infiltrating liver tissue.

Fig. 8.39 Immunoexpression of atz11 demonstratesalpha-1 antitrypsin deficiency of piz type.

A B

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are adjacent to a portal area. Within afibrous or hyalinized stroma, they presentas irregular or round ductal structuresthat appear somewhat dilated and havea flattened or cuboidal epithelium. Thelumina contain proteinaceous or bile-stained secretion. These lesions carry lit-tle or no malignant potential {736, 673}.

Bile duct adenoma (BDA)BDA is usually single and subcapsular,and is white and well circumscribed butnon-encapsulated. BDA is usually lessthan 1 cm in size, and is composed of aproliferation of small, normal appearingducts with cuboidal cells that have regu-lar nuclei and lack dysplasia {44}. Theseducts have no or little lumen and canelaborate mucin. Their fibrous stromashows varying degrees of chronic inflam-mation and collagenization. Enclosed inthe lesion are normally spaced portaltracts. They are considered to be a focalreaction to injury. BDA and peribiliary glands share com-mon antigens, suggesting a common lineof differentiation {136}. Occasionally, BDAcontains periductular endocrine cell clus-ters {1384}.In addition, there are several atypicalBDA with a neoplastic nature. Biliaryadenofibroma is characterized by a com-plex tubulocystic biliary epithelium with-out mucin production, together withabundant fibroblastic stromal compo-nents {1972}. Its expansive growth, andfoci of epithelial tufting, cellular atypiaand mitoses favor a neoplastic process.

Intrahepatic peribiliary cystsIn chronic advanced liver disease and

biliary anomalies, and also in normal liv-ers, multiple cysts may be seen aroundthe intrahepatic large bile ducts {1319,1320}. They are visible by ultrasound orCT. These cysts are derived from peribil-iary glands and should be differentiatedfrom ICC clinically and histologically.

Diffuse and multifocal hyperplasia of peri-biliary glandsDiffuse, severe, macroscopically recog-nizable dilatation and hyperplasia of theperibiliary glands of intrahepatic andextrahepatic bile ducts is a rare condition{1319, 437}. Some ducts may be cysti-cally dilated. Lack of familiarity with thislesion could lead to an erroneous diag-

nosis of a well-differentiated cholangio-carcinoma. It occurs in apparently nor-mal livers and also in acquired liver dis-eases.

Molecular genetics and genetic sus-ceptibilityMutations of the RAS and TP53 genes arethe most common genetic abnormalitiesidentified in ICC. The incidence of KRASmutations ranges from 100% and 60%among British {1054} and Japanesepatients respectively {1878, 1402}, to 4%among Thai patients {1510}. Taiwaneseand Korean patients show an intermedi-ate frequency {1037, 887}. The most fre-quently mutated position in the KRAS

Fig. 8.40 Bile duct adenoma. A Frozen section. B Cytokeratin immunostain showing characteristic branching pattern of bile ducts.

Fig. 8.41 Bile duct adenoma. Small, normal appearing proliferating bile ducts associated with a small con-nective tissue component and lymphocytic infiltration.

A B

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gene is codon 12 involving GGT (glycine)to GAT (aspartic acid). Less frequentmutations have been identified in codon13, involving GGT (glycine) to GAT(aspartic acid) and codon 61, involvingCAA (glutamine) to CAC (histidine) {1402,1969, 1511}. TP53 mutations occur between exons 5to 8, the most common change being Gto A transitions {887, 1511, 907, 1848}.The mutations are random with no spe-cific hot spot, being mostly missensemutations and less frequently nonsensemutations {887}. p53 protein is immuno-histochemically detectable in carcinomacells in more that 70% of ICC cases.KRAS and TP53 mutations correlate withthe gross morphology of ICC {1969,1401}; a higher prevalence of KRASgene alterations is found in the periduc-tal and spicular forming infiltrating sub-type compared to the slower growing,non-invasive mass-forming type. TP53mutations are prominent in the mass-forming type of ICC.The variable incidence of KRAS muta-tions in different populations of ICC mayreflect different aetiologies. O. viverriniinfection and increased consumption ofnitrates and nitrites are contributing fac-tors in Thailand where the incidence ofKRAS abnormalities is low {2025, 1446}. Overexpression of c-erbB-2 occurs in onefourth to about two thirds of carcinoma ofthe biliary tract, and may be used as aphenotypic marker for neoplastic transfor-mation {1912}. Membranous expression

of E-cadherin, alpha-catenin, and beta-catenin is reduced in a majority of ICCand this down-regulation correlates withICC at high-grade {91}.Overexpession of MET, the receptor forhepatocytes growth factor, occurs in ICCand correlates with tumour differentia-tion, being poorly expressed in poorlydifferentiated tumours {1912}. It also cor-relates with the markedly increased pro-liferation indices seen in precancerousglands and cholangiocarcinoma. Biliaryepithelial cells are continuously exposedto genotoxic insults such as chronicinflammation and hydrophobic bileacids, predisposing to oncogenic muta-tions. Progression to malignancy may bedue, in part, to failure in activating apop-tosis and deleting cells with geneticdamages {263}. The anti-apoptotic pro-tein bcl-2, is overexpressed in ICC {281}and telomerase activity is detectable incarcinoma cells of almost all ICC cases.

Prognosis and predictive factorsEarly detection of ICC is difficult, and theoverall prognosis after resection is poorcompared with that of HCC. Lymph nodespread, vascular invasion, positive mar-gins and bilobar distribution are associ-ated with a high recurrence rate and apoor prognosis. One study found the5-year survival rate was 39% in patientswith mass-forming tumours and 69% forintraductal tumours while no patients withmass-forming plus periductal-infiltratingtumours survived > 5 years {2161}.

Histologically, squamous cell or sarco-matous elements and mucinous variantsconfer a poor prognosis {1312, 1313}.Patients with well differentiated ICC seemto survive longer than those with moder-ately or poorly differentiated ones. A fewcases of well differentiated ICC withbland features resembling bile duct ade-noma show a good prognosis {522}.MUC 2 protein expression is relativelyfrequent in well differentiated ICC, sug-gesting a somewhat more favourableprognosis {1915}. Lymph node metastasis is a significantprognostic factor {2160}. The 5-year sur-vival rate in patients with lymph nodemetastases is significantly lower thanthat in patients without lymph nodemetastasis (51%). In liver fluke-associated ICC, survivalafter right hepatectomy is better thanafter left hepatectomy, and is not associ-ated with tumour size {1990}. In addition,multiple tumour masses have a poorprognosis. Concomitant hepatolithiasisprevents precise diagnosis preoperative-ly, and precipitates biliary sepsis. Long-term post-surgical survival of patientswith stone-containing ICC compared toICC alone is controversial {291, 1849}.ICC found in non-biliary cirrhosis is usual-ly detectable as a small nodule during fol-low-up of hepatitis virus-related cirrhosis,and is treatable with hepatectomy {2159}.

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181Combined hepatocellular and cholangiocarcinoma

DefinitionA rare tumour containing unequivocalelements of both hepatocellular andcholangiocarcinoma that are intimatelyadmixed.This tumour should be distinguishedfrom separate hepatocellular carcinomaand cholangiocarcinoma arising in thesame liver {605}. Such tumours may bewidely separated or close to each other(‘collision tumour’).

EpidemiologyThis tumour type comprises less than 1%of all liver carcinomas. There are similargeographical distribution differences asfor hepatocellular carcinoma and a simi-lar age and sex distribution.

Tumour spread and staging Some studies have found a higher fre-quency of lymph node metastasis com-pared with HCC.

MacroscopyGross inspection does not show signifi-cantly different morphology compared tohepatocellular carcinoma. In tumourswith a major cholangiocarcinomatouscomponent with fibrous stroma, the cutsurface is firm.

HistopathologyCombined hepatocellular and cholangio-carcinoma is the term preferred for atumour containing both hepatocellularand distinct or separate cholangiocarci-noma. The presence of both bile andmucus should be sought in the com-bined tumour. This category should notbe used for tumours in which either formof growth is insufficiently differentiatedfor positive identification. Hepatocytes preferentially express cytok-eratins 8 and 18 and, like duct epithelialcells, cytokeratins 7 and 19. However, thedifferent patterns of expression are not asclear-cut in these tumours. For practicalpurposes, demonstration of bile canaliculiby polyclonal CEA (mixed biliary glyco-proteins) combined with Hep Par immu-

noexpression is sufficient for the diagno-sis of a hepatocellular carcinomatouscomponent, and that of neutral epithelialmucin by the PAS-diastase reaction forthe diagnosis of a cholangiocarcinoma-tous component {1046, 1456, 667}.

Prognostic factorsSome authors have reported patientswith combined hepatocellular andcholangiocarcinoma having a worseprognosis as compared with patientswith HCC.

C. WittekindH.P. FischerT. Ponchon

Combined hepatocellular and cholangiocarcinoma

Fig. 8.42 Combined hepatocellular carcinoma andcholangiocarcinoma arising in non-cirrhotic liver tissue in a patient with heterozygous Piz type alpha-1 antitrypsin deficiency. A Pale, homogeneous cutsurface. B Microscopic, showing glandular areas.

Fig. 8.43 Combined hepatocellular and cholangio-cellular carcinoma. A Microtrabecular HCC andcholangiocarcinoma with desmoplastic response.B Border zone between HCC and cholangiocarci-noma.

A

B

A

B

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DefinitionA cystic tumour either benign (cystade-noma) or malignant (cystadenocarcino-ma), lined by epithelium with papillaryinfoldings that may be mucus-secretingor, less frequently, serous. Lesions arisefrom ducts proximal to the hilum of theliver. They differ from tumours that arisein cystic congenital malformation and inparasitic infections and hepatolithiasis.

EpidemiologyBile duct cystadenoma and cystadeno-carcinoma are rare {809}. Cystadenomais seen almost exclusively in females,with cystadenocarcinoma appearingequally in males and females. The aver-age age of patients is 50-60 years.

Clinical featuresPatients often present with abdominalpain and mass. A few patients have jaun-dice. Elevated serum levels of tumourmarker CA 19-9 may occur. Imagingtechniques show multilocular cystictumour(s), occasionally with tiny papillaryfolds in the cystic wall.

MacroscopyThe cysts are usually multilocular andtypically range from 5 to 15 cm diameter{809}. In cystadenocarcinoma, a largepapillary mass may occur as well as

solid areas of grey-white tumour in athickened wall.

Tumour spread and stagingCystadenocarcinomas show intrahepaticspread and metastasis to regional lymphnodes in the hepatoduodenal ligament.Distant metastases occur most frequent inthe lungs, the pleura and the peritoneum.Staging is performed according to theTNM Classification of liver tumours {66}.

HistopathologyCystadenomas are usually multilocularand are well defined by a fibrous cap-sule, which may contain smooth musclefibres. The contents of the locules areeither thin, opalescent or glairy fluid, ormucinous semisolid material. Two histological variants are recognized.The mucinous type is more common andis lined by columnar, cuboidal, or flat-tened mucus-secreting epithelial cellsresting on a basement membrane; poly-poid or papillary projections may be pres-ent. About 5% of the tumours reveal neu-roendocrine differentiation, as identifiedby expression of chromogranin andsynaptophysin. Subjacent to the base-ment membrane is a cellular, compactedmesenchymal stroma, which in turn issurrounded by looser fibrous tissue. Thismesenchymal component is seen only in

females and has been likened to ovarianstroma. The stromal cells expressvimentin, and there are many cells thatexpress smooth muscle actin. A xan-

C. WittekindH.P. FischerT. Ponchon

Bile duct cystadenoma and cystadenocarcinoma

Fig. 8.46 Bile duct cystadenoma. A Large peribiliary cysts in the connective tissue of the hilus; the background liver shows advanced cirrhosis. B Variably sized cystsare intermingled with peribiliary glands.

BA

Fig. 8.44 Biliary cystadenoma. The lining epitheliumis cuboidal and lies on ovarian-like stroma, beneathwhich is a band of dense tissue.

Fig. 8.45 Severe dysplasia in the epithelium of anintrahepatic large bile duct in a case of hepatolithi-asis.

8b 19.7.2006 8:18 Page 182

183Bile duct cystadenoma and cystadenocarcinoma

thogranulomatous reaction, with foamcells, cholesterol clefts and pigmentedlipofuscin-containing macrophages, maybe present in the cyst wall. The seroustype consists of multiple, small loculeslined by a single layer of cuboidal cellswith clear cytoplasm containing glyco-gen. The cells rest on a basement mem-brane but are not surrounded by themesenchymal stroma typical of the muci-nous variety. Squamous metaplasia mayalso occur.Cystadenocarcinomas are usually multi-locular and contain mucoid fluid. Malig-nant change may not involve all of theepithelium lining the cyst; it is usually mul-tifocal. The tumours are so well definedthat complete removal can usually be

achieved with good prognosis. Differenti-ation from intrahepatic bile duct cystade-noma depends on the demonstration ofcytological (particularly nuclear) atypia,mitosis, and invasion of the underlyingstroma.Some bile duct cystadenocarcinomasmay be misdiagnosed as bile duct cys-tadenomas because insufficient sam-pling results in tumour morphologyshowing no cytological features of malig-nancy or invasion of the underlying stro-ma {351, 809, 1268, 2096}.

Prognostic factorsThe prognosis of patients with biliaryduct cystadenocarcinomas is good if acurative resection is possible. The

course of patients with unresectabletumours seems to be better than ofpatients with cholangiocarcinoma {71}.

Fig. 8.47 Bile duct cystadenocarcinoma. Papillaryfolding with serous and mucinous neoplasticepithelium.

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DefinitionA malignant embryonal tumour withdivergent patterns of differentiation,ranging from cells resembling fetal epi-thelial hepatocytes, to embryonal cells,and differentiated tissues includingosteoid-like material, fibrous connectivetissue and striated muscle fibers.

EpidemiologyHepatoblastoma is the most frequentliver tumour in children. Four percent ofhepatoblastomas are present at birth,68% in the first two years of life and 90%by five years of age. Only 3% are seen inpatients over 15 years of age. A recentincrease in the incidence of tumours ininfants with birth weights below 1500grams has been reported {776, 777,1899}. There is a male predominance of1.5:1 to 2:1, but no racial predilection.

LocalizationHepatoblastomas occur as a singlemass in 80% of cases, involving the rightlobe in 57%, the left lobe in 15% andboth lobes in 27% of patients {1838}.Multiple masses, seen in the other 20%of cases, may occur in either or bothlobes.

Clinical featuresHepatoblastomas are often noted by aparent or physician as an enlargingabdomen in the infant that may be

accompanied by weight loss or anorexia.Less frequently nausea, vomiting, andabdominal pain are present. Jaundice isseen in 5% of cases. Rarely, tumour cellsmay produce human chorionic gona-dotrophin, leading to precocious pubertywith pubic hair, genital enlargement anddeepening voice, noted most prominent-ly in young boys. Hepatoblastoma is accompanied by ane-mia in 70% of cases and by thrombocy-tosis in 50%, with platelet counts exceed-ing 800 x 109/L in nearly 30% of cases{1717}. Alpha fetoprotein (AFP) is elevat-ed in about 90% of patients at the time ofdiagnosis. The levels of AFP parallel thecourse of the disease, falling to normallevels after complete removal of thetumour and rising with recurrence of thelesion. AFP levels may be normal or onlyslightly elevated with small cell undiffer-entiated hepatoblastoma. Caution mustbe taken in evaluating the levels of AFP inyounger infants since the ‘adult’ level ofAFP (< 25ng/mL) is not reached untilapproximately six months of age. Other laboratory abnormalities caninclude elevated levels of serum choles-terol, bilirubin, alkaline phosphatase, andaspartate aminotransferase {10}.

ImagingComputed tomography (CT) shows sin-gle or multiple masses within the liver,which in 50% of cases display calcifica-

tion {1233}. Magnetic resonance imaging(MRI) along with CT can help differentiatehepatoblastoma from infantile haeman-gioendothelioma, mesenchymal hamar-toma, and hepatocellular carcinoma bydemonstrating cystic or vascular featurespeculiar to each lesion {1999}. MRI mayalso be used to characterize epithelialand mesenchymal components of hepa-toblastoma {1533}.

MacroscopyHepatoblastomas vary in size from 5 to22 cm in diameter and from 150 to 1,400g in weight. Single and multiple lesionsmay be well circumscribed, the edge ofthe lesion being separated from the nor-mal liver by an irregular pseudocapsule.Pure fetal hepatoblastomas have the tan-brown colour of normal liver, while mixedhepatoblastomas display a variety ofcolours from brown to green to white. Thelesions are often nodular and bulge fromthe cut surface. Areas of necrosis andhaemorrhage are usually present andmay appear as soft or gelatinous, brownto red tissue {1837}.

Tumour spread At clinical manifestation, 40-60% ofhepatoblastomas are either very large orinvolve both lobes to the extent that theyare considered unresectable {1839}.Preoperative chemotherapy, however,reduces the size of the lesion in nearly85% of these patients to a size that ren-ders it resectable. Tumour spreadincludes local extension into the hepatic

J.T. StockerD. Schmidt

Hepatoblastoma

Hepatoblastoma 43.5 27.6Infantile haemangioendothelioma 36.1 16.5Mesenchymal hamartoma 13.3 8.0Hepatocellular carcinoma 1.4 18.9Focal nodular hyperplasia 1.1 10.1Undifferentiated "embryonal" sarcoma 1.1 7.2Nodular regenerative hyperplasia 2.1 4.5Hepatocellular adenoma 0.0 3.8Angiosarcoma 1.4 2.4Embryonal rhabdomyosarcoma 0.0 1.0

Birth to Birth to 2 years (%) 20 years (%)

Type of Tumour (285 cases) (716 cases)

Fig. 8.48 Hepatoblastoma in a patient 3 years ofage. The T2 weighted MRI shows a liver mass thathistologically corresponds to fetal epithelial hepa-toblastoma.

Table 8.02Age distribution of hepatic tumours in young patients. Data are from the Armed Forces Institute of Pathology(AFIP), Washington, DC (U.S.A.)

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185Hepatoblastoma

veins and inferior vena cava. The lung isthe most frequent site of metastases;approximately 10-20% of patients havepulmonary metastases when first diag-nosed. Hepatoblastomas also spread tobone, brain, ovaries, and the eye {179,1600, 619, 463}.

HistopathologyHepatoblastomas display a distinct vari-ety of histological patterns that may bepresent in varying proportions. Sometumours are composed entirely of uni-form fetal epithelial cells or small undif-ferentiated cells, while others contain avariety of tissue types including hepaticfetal epithelial and embryonal cells,fibrous connective tissue, osteoid-likematerial, skeletal muscle fibers, nests ofsquamous epithelial cells, and cells withmelanin pigment.

Pure fetal epithelial differentiationAccounting for nearly one third of cases,the fetal epithelial pattern is composed ofthin trabeculae of small cuboidal cellsresembling the hepatocytes of the devel-

oping fetal liver. These cells contain asmall round nucleus with fine nuclearchromatin and an indistinct nucleolus.The cytoplasm varies from finely granularto clear, reflecting variable amounts ofglycogen and lipid which can impart a'light and dark' pattern to the lesion whenviewed at lower magnifications. Cana-liculi may be seen between hepatocytesof the 2-3 cell layer trabeculae, but onlyrarely is bile stasis present. In biopsiestaken before preoperative chemothera-py, foci of extramedullary haemato-poiesis (EMH) composed of clusters oferythroid and myeloid precursors may bepresent in the sinusoids {2023}.Sinusoids are lined by endothelial andKupffer cells which show a more diffusestaining with UEA-1 and anti-CD34 thanthe focal staining of the sinusoidalendothelial cells of normal liver {1630}. The fetal phenotype has been signifi-cantly associated with both diploid DNAnuclear content and low proliferativeactivity assessed by flow cytometry andPCNA labeling index {1640}.

Combined fetal and embryonal epithelialApproximately 20% of cases display apattern combining fetal epithelial cellsand sheets or clusters of small, ovoid toangulated cells with scant amounts ofdark granular cytoplasm surrounding anucleus with increased nuclear chro-matin. The cells display little cohesive-ness but may cluster into pseudorosette,glandular or acinar structures. Thesesmall, round, blue cells resemble theblastemal cells seen in nephroblastomas,neuroblastomas and other 'embryonal'tumours in children. While often inter-mixed with the fetal epithelial cells, thefoci of embryonal cells, which are devoidof glycogen and lipid, can be identifiedby their absence of staining with PAS oroil red-O stains. Mitotic activity is morepronounced in the embryonal areas, andassociated with a low TGF-alpha expres-sion. EMH, in the absence of preopera-tive chemotherapy, may also be noted{925}.

MacrotrabecularIn about 3% of cases of fetal or fetal andembryonal epithelial hepatoblastomas,areas containing broad trabeculae (6-12or more cells in thickness) are present.These macrotrabeculae are composedof fetal and embryonal epithelial cellsand a third, larger cell type characterized

by more abundant cytoplasm and largernuclei. Although the trabeculae resemblethose seen in the pseudoglandular typeof hepatocellular carcinoma, the cellsdisplay only mild hyperchromasia andanisocytosis, and mitotic activity is low.The term 'macrotrabecular' is applied toonly those cases in which macrotrabecu-lae are a prominent feature of the lesion.If only an isolated focus is present, the

Stage I Complete resection

Stage II Microscopic residualNegative nodal involvementNo spilled tumour

Stage III Gross residual or Nodal involvement orSpilled tumour

Stage IV Metastatic disease

Table 8.03 Staging of Hepatoblastoma according to theChildren's Cancer Study Group (CCSG) classifica-tion.

Absence of left adrenal glandAcardia syndromeAlcohol embryopathyBeckwith-Wiedemann syndromeBeckwith-Wiedemann syndrome with opso-clonus, myoclonusBilateral talipes Budd-Chiari syndromeCleft palate, macroglossia, dysplasia of earlobesCystothioninuriaDown syndrome, malrotation of colon, Meckeldiverticulum, pectum excavatum, intrathoracickidney, single coronary arteryDuplicated uretersFetal hydropsGardner syndromeGoldenhar syndrome – oculoauriculovertebral dysplasia, absence of portal veinHemihypertrophyHeterotopic lung tissueHeterozygous α1-antitrypsin deficiencyHIV or HBV infectionHorseshoe kidneyHypoglycemiaInguinal herniaIsosexual precocityMaternal clomiphene citrate and PergonalMeckel diverticulumOral contraceptive, motherOral contraceptive, patientOsteoporosisPersistent ductus arteriosusPolyposis coli familiesPrader-Willi syndromeRenal dysplasiaRight-sided diaphragmatic herniaSchinzel-Geidion syndromeSynchronous Wilms tumourTrisomy 18Type 1a glycogen storage diseaseUmbilical herniaVery low birth weight

Table 8.04Clinical syndromes, congenital malformations andother conditions that have been associated withhepatoblastoma.

Fig. 8.49 Epithelial hepatoblastoma presenting as alarge, well demarcated lesion with central haemor-rhage.

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classification is based on the epithelial ormixed epithelial/mesenchymal compo-nents present.

Small cell undifferentiatedHepatoblastomas composed entirely ofnoncohesive sheets of small cells resem-

bling the small blue cells of neuroblas-toma, Ewing sarcoma, lymphoma, andrhabdomyosarcoma are called small cellundifferentiated hepatoblastomas andamount to about 3% of the tumours. Thistype is believed to represent the least dif-ferentiated form of hepatoblastoma{602}.While often difficult to identify as hepaticin origin, the presence of small amountsof glycogen, lipid and bile pigment,along with cytoplasmic cytokeratin, helpsseparate this lesion from metastatic smallcell tumours. The cells are arranged assolid masses with areas of cellularpyknosis and necrosis and high mitoticactivity. Sinusoids are present butdecreased in amount compared to thefetal epithelial pattern, and there is pro-nounced intracellular expression ofextracellular matrix proteins and largenumbers of fibers immunoreactive forcollagen type III {1629}.

Mixed epithelial and mesenchymalThe largest number of hepatoblastomas(44%) display a pattern combining fetaland embryonal epithelial elements withprimitive mesenchyme and mesenchy-mally derived tissues. Of these mixedtumours, 80% have only immature and

BA

Fig. 8.51 Pure fetal hepatoblastoma. A Cuboidal cells form trabeculae. B Immunoreactivity for alpha-fetoprotein is present in most tumour cells. A cluster ofhematopoietic cells is present at lower center.

BA

Fig. 8.53 Fetal and embryonal hepatoblastoma.Embryonal epithelial cells occur singly and in gland-like structures.

Fig. 8.52 Fetal and embryonal epithelial hepatoblas-toma. Fetal epithelial cells with a high cytoplasmiclipid concentration are separated by a band offibrous connective tissue from a vascular mass ofembryonal cells.

Fig. 8.50 Pure fetal epithelial hepatoblastoma. Variable concentrations of glycogen and lipid within tumour cells create dark and light areas.

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187Hepatoblastoma

mature fibrous tissue, osteoid-like tissueand cartilaginous tissue, in addition tothe epithelial cells. The other 20% con-tain additional elements. The mesenchymal elements of the 'sim-ple' mixed tumour are interspersed withthe fetal and embryonal epithelial ele-ments. The primitive mesenchymal tissueconsists of a light myxomatous stromacontaining large numbers of spindle-shaped cells with elongate nuclei. Thecells may display a parallel orientationwith collagen fibers and cells resemblingyoung fibroblasts. More mature fibroussepta with well differentiated fibroblastsand collagen may also be seen. Islands of osteoid-like tissue composed ofa smooth eosinophilic matrix containinglacunae filled with one or more cells arethe hallmark of the mixed lesion. Rarely,they are the only 'mesenchymal' compo-nent noted in a predominantly fetalepithelial hepatoblastoma. In fact, the'osteoid' material is positive for alpha1-antitrypsin, alpha 1-antichymotrypsin,alpha fetoprotein, carcinoembryonic anti-gen, chromogranin A, epithelial mem-brane antigen, vimentin and S-100 pro-tein, suggesting an origin from epithelialcells {10, 2058, 1629}. The cells within thelacunae, while 'osteoblast-like' with angu-lated borders, abundant eosino-philiccytoplasm and one or more round or ovalnuclei, may in some areas blend withadjacent areas of embryonal epithelialcells, further supporting their epithelialorigin. Cartilaginous material may also bepresent.

Mixed with teratoid featuresIn addition to the features noted in the'simple' mixed epithelial/mesenchymalhepatoblastoma, about 20% of lesionswill display additional features, includingstriated muscle, bone, mucinous epitheli-um, stratified squamous epithelium, andmelanin pigment {1839}. These tissuesmay occur separately or be admixed withothers. It is important to differentiatethese teratoid features from a true ter-atoma, which does not contain fetal andembryonal epithelial hepatoblastomaareas. There is, however, a single casereport of a discrete cystic teratoma con-tiguous to a hepatoblastoma {331}.

StagingThese is no official TNM classification forhepatoblastoma but a TNM-type systemhas been proposed {332}. The Children's

Cancer Study Group (CCSG) classifica-tion is widely used. While 40-60% ofpatients are considered inoperable at thetime they are first seen and 10-20% havepulmonary metastases, preoperativechemotherapy and transplantation for themore extensive lesions have resulted inresectability for nearly 90% of cases.

Precursor lesions and benign tumoursPrecursor lesions of hepatoblastomahave not been identified, but hepatoblas-toma must be differentiated from other

liver tumours and pseudotumours thatoccur in the same age period. Infantilehaemangioendothelioma, the most com-monly occurring benign tumour of theliver, is seen almost exclusively in the firstyear of life and presents as an asympto-matic mass or, less frequently, as con-gestive heart failure due to rapid shunt-ing of blood through the liver {1708}. MRIand arteriography are helpful in estab-lishing the diagnosis. Mesenchymal hamartoma, anotherbenign lesion, occurs during the first 2-3

Fig. 8.54 Pure fetal epithelial hepatoblastoma. Clusters of small, dark haematopoietic cells are present.

Fig. 8.55 Fetal and embryonal hepatoblastoma. The embryonal cells may resemble other blastemal cells, e.g.those encountered in nephroblastoma or neuroblastoma.

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years of life and presents as a rapidlyenlarging mass due to accumulation offluid within cysts formed in the mes-enchymal portion of the lesion {1841}. CTand MRI are useful in defining the cysticnature of the lesion. Focal nodular hyper-plasia and nodular regenerative hyper-plasia may be seen in the first few yearsof life but are more common in older chil-dren {1839}. Hepatocellular adenoma israrely seen in the first 5-10 years of life,but may be difficult to differentiate from apure fetal epithelial hepatoblastoma.

Genetic susceptibilityCongenital anomalies are noted inapproximately 5% of patients (Table 8.04)and include renal malformations such ashorseshoe kidney, renal dysplasia andduplicated ureters, gastrointestinal mal-formations such as Meckel diverticulum,inguinal hernia and diaphragmatic her-

nia, and other disparate malformationssuch as absent adrenal gland and het-erotopic lung tissue. Other syndromeswith an increased incidence of hepato-blastoma include Beckwith-Wiedemannsyndrome, trisomy 18, trisomy 21,Acardia syndrome, Goldenhar syndrome,Prader Willi syndrome, and type 1a glyco-gen storage disease {1585}.Hepatoblastoma and familial adenoma-tous polyposis (FAP) are associated dueto germline mutation of the adenomatouspolyposis coli (APC) gene. FAP kindredsinclude patients with hepatoblastomawho have an APC gene mutation at the5' end of the gene {267, 578}. Alterationsin APC have also been noted in cases ofhepatoblastoma in non-familial adeno-matous polyposis patients {1390}.

Molecular geneticsCytogenetic abnormalities include tri-

somy for all or parts of chromosome 2,trisomy for chromosome 20 and loss ofheterozygosity (LOH) for the telomericportion of 11p (11p15.5). The materiallost on 11p is always of maternal origin{43}. LOH has also been observed on theshort and long arms of chromosome 1with a random distribution of parental ori-gin for chromosome arm 1p and a pater-nal origin for chromosome arm 1q {970}. TP53 overexpression has beendescribed in several cases, but TP53mutations in exons 5 to 9 are infrequent{1406}. Increased copy numbers of c-metand K-sam proto-oncogenes and cyclinD1 genes have been described in a caseof hepatoblastoma in an adult patient{977}.The presence of oval cell antigen hasbeen demonstrated in hepatoblastomas,which supports the stem cell origin ofthese tumours {1631}.

Fig. 8.57 Mixed epithelial and mesenchymal hepatoblastoma. Areas showingmesenchymal tissue and foci of osteoid-like material are present, together withareas of epithelial hepatoblastoma.

Fig. 8.56 Macrotrabecular hepatoblastoma. On the left, the tumour consists ofmacrotrabeculae. The one to two-cell thick trabeculae of fetal epithelial hepa-toblastoma pattern are seen on the right.

Fig. 8.58 Mixed epithelial and mesenchymal hepatoblastoma with teratoid features. A Squamous differentiation. B Skeletal muscle fibres.BA

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189Hepatoblastoma

Prognosis and predictive factorsPrognosis is directly affected by the abil-ity to resect the lesion entirely, i.e. toattain Stage I or II following the initial sur-gery {332, 446, 648, 2024}. Chemo-therapy and transplantation haveallowed resectability in 90% of cases,increasing the overall survival to 65-70%.

Survival in Stage I is nearly 100% andStage II survival approaches 80%.AFP levels are useful in predicting out-come by observing their response to sur-gery and chemotherapy {1997}. AFP lev-els of 100 to 1,000,000 ng/mL at initialdiagnosis are associated with a betterprognosis than if they are < 100 or

> 1,000,000ng/mL. Other factors posi-tively influencing prognosis includetumour confined to one lobe, fetal epithe-lial growth pattern, and multifocal dis-semination (rather than unifocal growthpattern in the liver with distant metas-tases and vascular invasion) {2022}.

Fig. 8.59 Mixed epithelial and mesenchymal hepatoblastoma. Fetal epithelialcells upper left and embryonal epithelial cells upper right lie adjacent to a focusof osteoid-like material.

Fig. 8.60 Mixed epithelial and mesenchymal hepatoblastoma with teratoid fea-tures. This area resembling fetal hepatoblastoma contains black melanin pig-ment.

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DefinitionPrimary lymphoma of the liver is definedas an extranodal lymphoma arising in theliver with the bulk of the disease localizedto this site. Contiguous lymph nodeinvolvement and distant spread may beseen but the primary clinical presentationis in the liver, with therapy directed to thissite.

EpidemiologyPrimary lymphoma of the liver is rare{796}. It is mainly a disease of white mid-dle aged males {1043, 1217} although anoccasional case has been reported inchildhood {1557}. Most are B-cell lym-phomas. Primary hepatosplenic T-celllymphomas have a different distribution.Patients are almost always male (M:Fapproximately 5:1) but are usuallyyounger with a mean age of 20 years(range 8-68 years) {334}. In contrast to primary lymphoma, sec-ondary liver infiltration is a frequentoccurrence, being present in 80-100% ofcases of chronic leukaemia, 50-60% ofcases of non-Hodgkin lymphoma andapproximately 30% of cases of multiplemyeloma {2042, 261}.

AetiologyA proportion of cases are associatedwith hepatitis C virus infection with andwithout mixed cryoglobulinaemia {390,56, 1257, 90, 371, 1625, 311}. Other lym-phomas have been reported arising with-in a background of hepatitis B virusinfection {1441, 1183}, HIV infection{1680, 1516} and primary biliary cirrhosis{1535}.

Clinical features The most frequent presenting symptomsare right upper abdominal/epigastricpain or discomfort, weight loss and fever{1043, 1217}. Most cases are solitary ormultiple masses within the liver whichmay be misdiagnosed as a primary livertumour or metastatic cancer {1043,1217}. Some cases have been reportedwith diffuse infiltration of the liver associ-ated with hepatomegaly but without a

discrete mass, simulating hepatic inflam-mation {668}.Hepatosplenic T-cell lymphomas presentwith hepatosplenomegaly, usually withoutperipheral lymphadenopathy and withoutlymphocytosis. There is almost alwaysthrombocytopenia and most patients areanaemic. Liver function tests are usuallyabnormal with moderate elevation of lev-els of transaminases and alkaline phos-phatase. Serum lactate dehydrogenaselevel may be very high {334}.

Histopathology B-cell lymphomaThe majority of primary hepatic lym-phomas are of diffuse large B-cell typewith sheets of large cells with large nucleiand prominent nucleoli. Phenotypicallythese characteristically express the panB-cell markers CD20 and CD79a. Occasional cases of Burkitt lymphomahave been described {759} in which themorphology is typical of Burkitt lym-phoma encountered elsewhere in thedigestive tract. Immunophenotypicallythe cells express CD20, CD79a andCD10. They are generally negative withantibodies to bcl-2 protein.Low-grade B-cell lymphomas of MALTtype have also been described. Theseare characterized by a dense lymphoidinfiltrate within the portal tracts. The atyp-ical lymphoid cells have centrocyte-likecell morphology and surround reactivegerminal centres. Lymphoepitheliallesions are formed by the centrocyte-likecells and the bile duct epithelium, andthese may be highlighted by staining withanti-cytokeratin antibodies. Nodules ofnormal liver may be entrapped within thetumour. The cells express pan-B-cellmarkers CD20 and CD79a and are nega-tive for CD5, CD10 and CD23. There is noexpression of cyclinD1 {797, 1143, 923}.Secondary involvement of the liver bychronic lymphocytic leukaemia andB-cell non-Hodgkin lymphoma tends toshow a distribution involving the portaltriads although nodular infiltration mayalso be seen with non-Hodgkin lym-phoma and multiple myeloma {2042}.

Hepatosplenic T-cell lymphomaThis is characterized by infiltration of thesinusoids by a monomorphic populationof medium sized cells with a moderateamount of eosinophilic cytoplasm. Thenuclei are round or slightly indented withmoderately dispersed chromatin andcontain small, usually basophilic, nucle-oli. There may be mild sinusoidal dilationand there are occasional pseudo-pelioticlesions. Perisinusoidal fibrosis may bepresent. Portal infiltration is variable. Asimilar sinusoidal pattern of infiltration isseen in the spleen and bone marrowboth of which are usually involved by thelymphoma at diagnosis {486, 334}.The cells are usually immunoreactive forCD2, CD3, CD7 and the cytotoxic gran-ule related protein TIA-1. There is usuallyno expression of CD5. The majority ofcases are CD4-/CD8+ although someare CD4-/CD8- {486, 334}. A CD4+ vari-ant has been described very infrequent-ly {771}. There is variable expression ofCD16 and CD56. All cases are negativefor βF1 and positive with antibodies forthe T-cell receptor δ.

GeneticsHepatosplenic T-cell lymphoma exhibitsrearrangement of the T-cell receptor γgene. EBV sequences have not beendetected {334}. Cytogenetic studieshave shown isochromosome 7q in anumber of cases and in some this hasbeen present as the sole cytogeneticabnormality {524, 48}

PrognosisThe prognosis of primary hepatic lym-phoma is generally poor. Chemotherapyor radiotherapy alone has been reportedto be ineffective but combination modali-ties, including surgery in resectablecases, can give relatively good results.{1043, 1217}. Hepatosplenic T-cell lym-phomas are very aggressive, with amean survival of 1 year {334} althoughthe CD4+ subtype may be associatedwith a slightly longer survival {771}.

A. WotherspoonLymphoma of the liver

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191Mesenchymal tumours

DefinitionBenign and malignant tumours arising inthe liver, with vascular, fibrous, adiposeand other mesenchymal tissue differenti-ation.

ICD-O codesICD-O codes, terminology, and defini-tions largely follow the WHO ‘HistologicalTyping of Soft Tissue Tumours’ {2086}.

ImagingImaging studies establish the presenceof a space-occupying lesion or lesions inthe liver, and may provide a diagnosis ordifferential diagnosis {1565}. Biopsy of amass is, however, needed for a definitivediagnosis {806}.

Mesenchymal hamartoma Mesenchymal hamartoma is a ‘tumourmalformation’ that develops in utero. Itaccounts for 8% of all liver tumours andpseudotumours from birth to 21 years ofage, but during the first two years of lifeit represents 12% of all hepatic tumoursand pseudotumours, and for 22% of thebenign neoplasms {1839}. It usuallymanifests in the first two years of life andthere is a slight male predominance.Lesions involve the right lobe in 75% ofcases, the left lobe in 22% and bothlobes in 3%. Presentation is typically with abdominalswelling, but rapid accumulation of fluidin the tumour can cause sudden enlarge-ment of the abdomen {1841}. Macrosco-pically, it is usually a single mass that canattain a large size (up to 30 cm or more).Mesenchymal hamartoma has an excel-lent prognosis after resection. The fate ofuntreated lesions is not known but thereis no convincing evidence of malignanttransformation.Histopathology. This tumour-like lesion iscomposed of loose connective tissue andepithelial ductal elements in varying pro-portions. Grossly, the cut surfaces exhib-it solid, pink-tan areas and cysts contain-ing a clear fluid. Histologically, the con-nective tissue is typically loose and oede-matous with a matrix of acid mucopoly-

K.G. IshakP.P. AnthonyC. NiederauY. Nakanuma

Mesenchymal tumours of the liver

DCFig. 8.61 Mesenchymal hamartoma. A Cut surface shows cysts and tan-white tissue. B Mixture of bile ducts,mesenchymal tissue and blood vessels. C Bile ducts display a ductal plate malformation; the primitive mes-enchymal tissue consists of loosely arranged stellate cells. In addition to blood vessels, the tumour also con-tains liver cells (top). D Fluid accumulation in the mesenchyme mimics lymphangioma, but the spaces lackan endothelial lining.

BA

Asymptomatic (incidental finding) AnyUpper abdominal mass +/- hepatomegaly AnySudden increase in size of tumour Mesenchymal hamartoma,

cavernous haemangiomaFebrile illness with weight loss Inflammatory pseudotumour,

embryonal sarcoma, angiosarcomaAcute abdominal crisis from rupture Cavernous haemangioma, angiosarcoma,

epithelioid haemangioendotheliomaBudd-Chiari syndrome Epithelioid haemangioendotheliomaCongestive heart failure Infantile haemangioendotheliomaCardiac tumour syndrome Embryonal sarcomaConsumption coagulopathy Cavernous haemangioma,

infantile haemangioendotheliomaHypoglycaemia Solitary fibrous tumourPortal hypertension Epithelioid haemangioendothelioma,

inflammatory pseudotumour Liver failure Epithelioid haemangioendothelioma,

angiosarcomaObstructive jaundice Inflammatory pseudotumourLung metastases Epithelioid haemangioendothelioma,

angiosarcoma

Mode of Presentation Examples

Table 8.05Presentation of mesenchymal tumours of the liver.

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saccharide, or it is collagenous andarranged concentrically around theducts. Fluid accumulation leads to sepa-ration of the fibres with formation of lym-phangioma-like areas and larger cavities.The epithelial component consists of bileducts that may be tortuous and occa-sionally dilated. The ducts often arearranged in a ductal-plate-malformationpattern. Islets of liver cells without an aci-nar architecture may be present.Numerous arteries and veins are scat-tered throughout, as are foci of extra-medullary haematopoiesis.

Infantile haemangioendotheliomaThis lesion is defined as a benign tumourcomposed of vessels lined by plumpendothelial cells, intermingled with bileducts, that are set in a fibrous stroma.Infantile haemangioendothelioma ac-counts for about one fifth of all livertumours and pseudotumours from birth to21 years of age. It usually presents in thefirst two years of life, when it represents40% of all tumours and pseudotumoursand 70% of the benign ones {1839}. Itoccurs more frequently in females (63%)than in males. Infantile haemangioen-dothelioma is a localized ‘tumour malfor-mation’ that develops in utero. There maybe a variety of associated congenitalanomalies, including hemihypertrophy

and Cornelia de Lange syndrome.Patients may develop congestive heartfailure or consumption coagulopathy, withor without an abdominal mass {397,1708}, and about 10% have haeman-giomas of the skin.Grossly, infantile haemangioendothe-lioma forms a single large mass (55%) orinvolves the entire liver by multiplelesions (45%). The single tumours have amaximum diameter up to 14 cm while themultiple lesions are often less than a cen-timeter. The large, single lesions are red-brown or red-tan, often with haemorrhag-ic or fibrotic centers and focal calcifica-tion. The small lesions appear spongyand red-brown on sectioning. Histopathology. Lesions are composedof numerous small vascular channels

lined by plump endothelial cells usuallyarranged in a single layer, but multilayer-ing and tufting can occur. The vesselsare supported by a scanty fibrous stromathat may be loose or compact. Largercavernous vessels with a single layer offlat endothelial cells are often present inthe centre of the larger lesions; thesevessels may undergo thrombosis withinfarction, secondary fibrosis and calcifi-cation. Other characteristic features ofinfantile haemangioendothelioma aresmall bile ducts scattered between thevessels, and foci of extramedullaryhaematopoiesis. Endothelial cells in thetumour express Factor VIII-related anti-gen and CD34.Prognosis. Infantile haemangioendothe-lioma has an overall survival of 70%;adverse risk factors include congestiveheart failure, jaundice and the presenceof multiple tumours {1708}. Singletumours are generally resected althoughsome 5-10% undergo spontaneous re-gression. Hepatic artery ligation or trans-arterial embolization are other therapeu-tic modalities. There are occasionalreports of transformation of infantile hae-mangioendothelioma to angiosarcoma{1708}.

Cavernous haemangioma This is the most frequently occurringbenign tumour of the liver. The reportedincidence varies from 0.4 to 20%, thehighest figure being the result of a thor-ough prospective search {892}. It is morefrequent in females, and occurs at allages but is least common in the paedi-atric age group. Although it usually pres-ents in adults, it is thought to be a hamar-tomatous lesion. It is known to increase insize or even rupture during pregnancy,and also may enlarge or recur in patientson oestrogen therapy. Consumptioncoagulopathy may occur. Cavernous

Fig. 8.62 Infantile haemangioendothelioma. A Red and brown tumour with focal hemorrhage. B Multiplebrown cavitary lesions. C The tumour is well circumscribed but not encapsulated, and consists of small ves-sels. D Masson trichrome stain shows vessels lined by a single layer of plump endothelial cells surroundedby a scant fibrous stroma. Note the scattered bile ducts.

BA

DC

BAFig. 8.63 Cavernous haemangioma. A Multilocular blood-filled structures with pale solid areas. B Large thin-walled vascular spaces.

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haemangiomas are not known to under-go malignant change. Only large symp-tomatic tumours require surgical exci-sion.Macroscopically, cavernous haeman-giomas vary from a few millimeters tohuge tumours (‘giant’ haemangiomas)that can replace most of the liver. Theyare usually single, and soft or fluctuant.When sectioned they partially collapsedue to the escape of blood and have aspongy appearance. Recent haemor-rhages, organized thrombi, fibrosis andcalcification may be seen. Histopathology. Lesions are typicallycomposed of blood-filled vascular chan-nels of varied size lined by a single layerof flat endothelial cells supported byfibrous tissue. Thrombi in various stagesof organization with areas of infarctionmay be present, and older lesions showdense fibrosis and calcification. In scle-rosed haemangiomas, most or all of thevessels are occluded and sometimes areonly demonstrable by stains for elastictissue.

AngiomyolipomaThe lesion is defined as a benign tumourcomposed of variable admixtures of adi-pose tissue, smooth muscle (spindled orepithelioid), and thick-walled blood ves-sels. The age range of angiomyolipomais from 30-72 years, with a mean of 50years {1373}. It is seen equally in malesand females {604}. A small number areassociated with tuberous sclerosis. Angiomyolipomas are usually single, with60% located in the right lobe, 30% in theleft lobe, 20% in both lobes and 8% in thecaudate lobe {1373}. They are sharplydemarcated but not encapsulated, fleshyor firm and, when sectioned, with ahomogeneous yellow, yellow-tan or tanappearance, depending on their contentof fat.Histopathology. Angiomyolipomas arecomposed of adipose tissue, smoothmuscle and thick-walled, sometimeshyalinized blood vessels in varying pro-portions. Morphologically and phenotyp-ically they are believed to belong to afamily of lesions characterized by prolif-eration of perivascular epithelioid cells{2197}. The smooth muscle is composedof spindle-shaped cells arranged in bun-dles, or larger more rounded cells withan ‘empty’ (glycogen-rich) cytoplasm oran eosinophilic, epithelioid appearance.The nuclei of the spindle cells are elon-

gated with blunt ends, but the largersmooth muscle cells can have large,hyperchromatic nuclei with prominentnucleoli. The microscopic appearancesare extensively varied and may imitateseveral malignant tumours, e.g. leio-myosarcoma, malignant fibrous histiocy-toma and hepatocellular carcinoma

{1971}. A characteristic feature of angio-myolipoma is the presence of extra-medullary haematopoiesis. The smoothmuscle cells contain variable quantitiesof melanin and express the melanomamarkers HMB-45 and Melan-A. They alsoexpress muscle specific actin andsmooth muscle actin.

Fig. 8.64 Sclerosed haemangioma. Pale hyalinizednodule with remnants of obliterated vessels.

Fig. 8.65 Lymphangioma. Lymphatic channels ofvariable size contain clear pink fluid.

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Fig. 8.66 Angiomyolipoma. A Fat within the tumour imparts a yellow colour. B Fat and smooth muscle arepresent. C Two characteristically thick-walled arteries are surrounded by fat. D This tumour is composedpredominantly of smooth muscle. The clear cytoplasm is due to glycogen that was lost during processing. E Large smooth muscle cells show perinuclear condensation of cytoplasm. F Marked extramedullaryhaematopoiesis.

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Solitary fibrous tumourSolitary fibrous tumour has an age rangefrom 32-83 years (mean, 57 years){1270}. Its aetiology is unknown. Lesionsvary considerably in size, from 2-20 cm indiameter {1270}. They arise in either lobeand are occasionally pedunculated. Theexternal surface is smooth and the con-sistency firm. They are sharply demarcat-ed but not encapsulated. Gross sectionsshow a light tan to almost white colourwith a whorled texture.Histopathology. Solitary fibrous tumouroften shows alternating cellular and rela-tively acellular areas. The cellular areasconsist of bundles of spindle cellsarranged haphazardly or in a storiformpattern. There is a well-developed retic-ulin network. In some cases the cells arearranged around ectatic vessels in a hae-mangiopericytoma-like pattern. Nuclei ofthe spindle cells are uniform and lackpleomorphism, but these tumours mayundergo malignant change as evidencedby the presence of foci of necrosis,prominent cellular atypia, and mitoticactivity in the range of 2-4 mitoses/10 hpf{1270, 514}. The relatively acellular areasof solitary fibrous tumour contain abun-dant collagen bundles with thin,stretched-out tumour cells. The tumourcells characteristically express CD34.

Inflammatory pseudotumourThis lesion is defined as a benign, non-neoplastic, non-metastasizing masscomposed of fibrous tissue and prolifer-ated myofibroblasts, with a markedinflammatory infiltration, predominantlyplasma cells {318}.The mean age at presentation of inflam-matory pseudotumour of the liver is 56years (range, 3-77) {438}; it is commonerin males (70%) than in females {1270}.Inflammatory pseudotumours are solitary(81%) or less often multiple (19%) {1275}and usually intrahepatic, but some caninvolve the hepatic hilum. About half of thesolitary tumours are located in the rightlobe. They vary in size from 1 cm to largemasses involving an entire lobe, and arefirm, tan, yellow-white or white. Someinflammatory pseudotumours are proba-bly the residuum of a resolved bacterialabscess, while others may be related toEpstein-Barr virus infection {82, 318}. Histopathology. The lesions are similar tothose occurring in other sites. They arecomposed of inflammatory cells in a stro-ma of interlacing bundles of myofibro-

blasts, fibroblasts, and collagen bundles.The majority of inflammatory cells aremature plasma cells, but lymphocytes(and occasional lymphoid aggregates orfollicles), as well as eosinophils and neu-trophils, may be present. Macrophages,sometimes showing xanthomatouschanges, occasional granulomas and,rarely, phlebitis involving portal veinbranches or outflow veins, may be seen.

Lymphangioma and lymphangiomatosisLymphangioma is a benign tumour char-acterized by multiple endothelial-linedspaces that vary in size from capillarychannels to large, cystic spaces contain-ing lymph. The vascular spaces are linedby a single layer of endothelial cells,though papillary projections or tuftingmay be seen. The cells rest on a basement membraneand the supporting stroma is usuallyscanty. Clear, pink-staining lymph fills thelymphatic channels.Hepatic lymphangiomatosis, often ac-companied by lymphangiomatosis of thespleen, skeleton, and other tissues, mayrepresent a malformation syndrome.Diffuse lymphangiomatosis involving theliver and multiple organs is associatedwith a poor prognosis. Single lesions havebeen successfully resected.

PseudolipomaPseudolipoma is believed to represent anappendix epiploica attached to theGlisson capsule after becoming detachedfrom the large bowel {1609}. Lesions areusually a small, encapsulated mass of fatlocated in a concavity on the surface ofthe liver, the fat typically showing necrosisand calcification {891}.

Focal fatty changeFocal fatty change of the liver is charac-terized by multiple, contiguous acinishowing macrovesicular steatosis ofhepatocytes, with preservation of acinararchitecture {804}. About 45% of casesof a series of focal fatty change occurredin patients with diabetes mellitus {632}.

Embryonal sarcomaA malignant tumour composed of mes-enchymal cells that, by light microscopy,are undifferentiated. Embryonal sarcoma (‘undifferentiated’sarcoma) comprises 6% of all primaryhepatic tumours in childhood {2082}. Itusually occurs between 5 and 20 yearsof age {1840}. Rarely, cases haveoccurred in middle and even old age.The incidence in males and females isequal {1840}. Embryonal sarcoma is ofunknown aetiology, although one patienthad a past history of prenatal exposure

DCFig. 8.67 Embryonal sarcoma. A Yellow and brown tumour with necrotic and haemorrhagic areas. B Smallnodule in the pseudocapsule and a tumour thrombus in a vessel. Multiple bile ducts are entrapped in the sar-comatous tissue. C Spindle and stellate cells together with giant cells in a loose myxoid stroma. D Pleomorphic cells with eosinophillic cytoplasmic globules.

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to phenytoin {148}. Symptoms includeabdominal enlargement, fever, weightloss, and nonspecific gastrointestinalcomplaints {1840}. Rarely, the tumourinvades the vena cava and grows intothe right atrium, mimicking a cardiactumour {561}. Macroscopy. Embryonal sarcoma isusually located in the right lobe of the liver, and varies from 10-20 cm indiameter. It is typically well-demarcatedbut not encapsulated. Gross sectionsreveal a variegated surface with glisten-ing, solid, grey-white tumour tissue alter-nating with cystic, gelatinous areasand/or red and yellow foci of haemor-rhage or necrosis.Histopathology. Embryonal sarcoma iscomposed of malignant stellate or spin-dle cells that are compactly or looselyarranged in a myxoid stroma. Tumourcells often show prominent anisonucleo-sis with hyperchromasia; giant cells thatmay be multinucleated are seen in manycases. A characteristic feature is thepresence of eosinophilic globules of var-ied size, sometimes many per cell, in thecytoplasm. They are PAS-positive, resistdiastase digestion, and express alpha-1antitrypsin, though the larger globulesmay only be immunoreactive at theperiphery. Entrapped bile ducts andhepatocellular elements are often pres-ent in the peripheral areas of thesetumours. The spindle, stellate and giantcells typically show no morphologicalevidence of differentiation, but immuno-histochemical studies in a few caseshave demonstrated widely divergent dif-ferentiation into both mesenchymal andepithelial phenotypes, probably from aprimitive stem cell {1460}. Prognosis. Until recently the prognosisof embryonal sarcoma has been verypoor, with a median survival of less thanone year after diagnosis {1840}. The sur-vival has greatly improved in the last sev-

eral years with some patients living fiveor more years after combined modalitytherapy (surgical resection, radiothera-py, and chemotherapy).

Kaposi sarcomaThis lesion is defined as a tumour com-posed of slit-like vascular channels, spin-dle cells, mononuclear inflammatorycells, with an admixture of haemosiderin-laden macrophages.Kaposi sarcoma involves the liver in 12-25% of fatal cases of the acquiredimmunodeficiency syndrome (AIDS), butis not known to contribute significantly toits morbidity and mortality. In patientswith AIDS, it is aetiologically related toHHV-8 infection {276, 1367}. It involvesportal areas but can infiltrate the adja-cent parenchyma for short distances,and is characterized grossly by irregular,variably-sized, red-brown lesions scat-tered throughout the liver.

Histologically, lesions resemble thoseoccurring in other sites with spindle cellsshowing elongated or ovoid, vesicularnuclei with rounded ends and inconspic-uous nucleoli. Eosinophilic, PAS-positiveglobules may be seen in the cytoplasm.The tumour cells are separated by slit-like vascular spaces . Aggregates ofhaemosiderin granules may be present.The spindle cells express endothelial cellmarkers (CD31, CD34).

Epithelioid haemangioendotheliomaA tumour of variable malignant potentialthat is composed of epithelioid or spindlecells growing along preformed vessels orforming new vessels.Epithelioid haemangioendothelioma pre-sents between 12 and 86 years (mean 47years) {807, 1150}. Its overall incidence isunknown, but more are reported infemales (61%) than in males (39%) {807,1150}. Risk factors are not known; the

Fig. 8.69 Epithelioid haemangioendothelioma. There is extensive destruction of liver cell plates. Note theintracellular vascular lumina (arrow).

B CAFig. 8.68 Kaposi sarcoma. A Multiple dark brown lesions centered in large portal areas. B, C Spindle cells and slit-like vascular spaces.

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suggestion of a relationship to oral con-traceptive use has not been validated{1270}. Epithelioid haemangioendothe-lioma causes systemic symptoms (weak-ness, malaise, anorexia, episodic vomit-ing, upper abdominal pain, and weightloss) and hepato-splenomegaly {807,1150}. Some patients develop jaundiceand liver failure. Uncommon modes ofpresentation include the Budd-Chiari syn-drome {2040} or portal hypertension.Macroscopy. Macroscopically, lesionsare usually multifocal; ill-defined lesionsscattered throughout the liver vary from afew millimeters to several centimeters ingreatest dimension. They are firm, tan towhite on sectioning, and often have ahyperaemic periphery; calcification maybe evident grossly.Histopathology. The tumour nodules areill-defined, and often involve multiplecontiguous acini. In actively proliferatinglesions the acinar landmarks, such asterminal hepatic venules (THV) and por-tal areas, can be recognized despiteextensive infiltration by the tumour. Thecells grow along preexisting sinusoids,THV, and portal vein branches, and ofteninvade Glisson capsule. Growth withinthe acini is associated with gradual atro-phy and eventual disappearance of livercell plates. Intravascular growth may bein the form of a solid plug, or a polypoidor tuft-like projection.

Neoplastic cell are either ‘dendritic’, withspindle or irregular shapes and multipleinterdigitating processes, ‘epithelioid’,with a more rounded shape and an abun-dant cytoplasm, or ‘intermediate’.Nuclear atypia and mitoses are mainlyobserved in the epithelioid cells. Cyto-plasmic vacuoles, representing intracel-lular vascular lumens, are often identifiedand may contain erythrocytes. Thetumour cells synthesize factor VIII-relatedantigen (von Willebrand factor), whichcan be demonstrated in the cytoplasm orin the neoplastic vascular lumens. Otherendothelial cell markers, such as CD31and CD34, are also positive. The stroma can have a myxoid appear-ance due to an abundance of sulphatedmucopolysaccharide. Reticulin fibres sur-round nests of tumour cells. Basementmembrane can be demonstrated aroundthe cells by the PAS stain, as well as ultra-structurally and immunohistochemically.Variable numbers of smooth muscle cellssurround the basement membrane. As the lesions evolve they are associatedwith progressive fibrosis and calcification.Eventually, tumour cells (and indeed, thevascular nature of the lesion) may be diffi-cult if not impossible to recognize in thedensely sclerosed areas. Needle biopsyspecimens taken from such areas oftenpose diagnostic problems. The histopa-thological differential diagnosis includes

angiosarcoma and cholangiocarcinoma.Angiosarcoma is much more destructivethan epithelioid haemangioendothelioma,obliterates acinar landmarks and resultsin cavity formation. Cells of cholangiocar-cinoma are arranged in a tubular or glan-dular pattern, and often produce mucin;the cells are cytokeratin positive and donot express endothelial cell markers.Prognosis. The clinical outcome ofepithelioid haemangioendothelioma isunpredictable, with some patients havinga fulminant course and others survivingmany years with no therapy. A recentstudy {1150} showed a correlationbetween high cellularity of the tumourwith a poor clinical outcome. Successfultreatment includes resection, when feasi-ble, and liver transplantation.

AngiosarcomaA malignant tumour composed of spindleor pleomorphic cells that line, or growinto, the lumina of preexisting vascularspaces, such as liver sinusoids andsmall veins.Worldwide, about 200 cases of angiosar-coma are diagnosed annually {848, 59}.During the period 1973-87, the SEERdatabase of the US National CancerInstitute contained 6,391 histologically-confirmed primary liver cancers; of theseonly 65 (1%) were angiosarcomas {252}.The peak incidence is in the 6th and 7thdecades of life. The male to female ratiois 3:1 {1085}.75% of angiosarcomas of the liver haveno known aetiology {484}. The remainderhave been linked to prior administrationof Thorotrast (a radioactive material con-taining thorium dioxide, that was used asan angiography contrast medium fromthe 1930s to the early 1950s), exposureto vinyl chloride monomer (VCM) or inor-ganic arsenic, and the use of andro-genic-anabolic steroids {484}.Patients with angiosarcoma present inone of several ways: 61% have symp-toms referable to the liver (e.g. hepato-megaly, abdominal pain, ascites); 15%have an acute abdominal crisis due tohaemoperitoneum from rupture of thetumour; 15% have splenomegaly, oftenwith pancytopenia; and 9% present dueto distant metastases {804}. The progno-sis of angiosarcoma is very poor, withmost patients dying within 6 months ofdiagnosis.Macroscopy. Angiosarcoma typicallyaffects the entire liver. Grayish-white

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DCFig. 8.70 Epithelioid haemangioendothelioma. A, B Tumour cells form polypoid projections in dilated peri-portal sinusoids. C Dendritic tumour cells, some having intracellular vascular lumina appearing as small vac-uoles. A terminal hepatic venule is infiltrated by tumour. D Tumour cells express factor VIII-related antigen.

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tumour alternates with red-brown haem-orrhagic areas. Large cavities withragged edges, filled with liquid or clottedblood, may be present. A reticular pat-tern of fibrosis is seen in cases related toprior exposure to Thorotrast.

Histopathology. Tumour cells grow alongpreformed vascular channels (sinusoids,THV and portal vein branches). Sinus-oidal growth is associated with progres-sive atrophy of liver cells and disruptionof the plates, with formation of larger vas-

cular channels and eventually the devel-opment of cavities of varied size. Thesecavities have ragged walls lined bytumour cells, sometimes with polypoid orpapillary projections, and are filled withclotted blood and tumour debris. Reti-

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Fig. 8.71 Angiosarcoma. A Multiple dark brown tumour foci scattered throughout the liver. B Solid portion showing spindle cells and numerous small vascular channels. C Intravascular papillary structure covered by neoplastic endothelial cells. D Tumour cells express CD34.

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Fig. 8.72 Angiosarcoma. A Sinusoidal spread of tumour cells with destruction of hepatocyte plates. B Disrupted liver cells act as scaffolding for the tumour cells.BA

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culin fibres and, less often, collagenfibres support the tumour cells. Perithelialcells, reactive for alpha-smooth muscleactin, may also be present. The tumourcells are sometimes packed solidly innodules that resemble fibrosarcoma. The cells of angiosarcoma are spindle-shaped, rounded or irregular in outline,and often have ill-defined borders. Thecytoplasm is lightly eosinophilic, andnuclei are hyperchromatic and elongatedor irregular in shape. Nucleoli can besmall, or large and eosinophilic. Large,bizarre nuclei and multinucleated cellsmay be seen, and mitotic figures are fre-quently identified. The spindled cellshave ill-defined outlines, a lightly eosino-philic cytoplasm, and vesicular nucleiwith blunt ends. Factor VIII-related anti-gen can be identified in tumour cellsimmunohistochemically. Other usefulmarkers include CD31 and CD34; the for-mer is believed to be the most sensitiveimmunostain {1224}. Invasion of THV and portal vein branch-es leads to progressive obstruction of the

lumen, and readily explains the frequent-ly encountered areas of haemorrhage,infarction, and necrosis. Haematopoieticactivity is observed in the majority oftumours.Cases related to Thorotrast and vinylchloride monomer are often associatedwith considerable periportal and sub-capsular fibrosis. Thorotrast deposits arereadily recognized in reticuloendothelialcells, in connective tissue of portal areas,in Glisson capsule, or in the walls of THV.The deposits are coarsely granular andrefractile, and in an H&E-stained sectionthey have a pink-brown hue. They arereadily visualized by scanning electronmicroscopy, and thorium can be defini-tively identified by energy dispersive X-ray microanalysis {804}.Genetics. Analysis of six hepatic angio-sarcomas associated with VCM expo-sure found three TP53 mutations, allA:T→T:A transversions, which are other-wise uncommon in human cancers {728}.Another study of 21 sporadic angiosar-comas not associated with vinyl chloride

exposure found TP53 mutations to beuncommon, thus supporting previousevidence of the carcinogenic potential ofchloroethylene oxide, a metabolite ofVCM {1776}. A high rate of KRAS-2 muta-tions has been found in both sporadicand Thorotrast-induced angiosarcomasof the liver {1542}. Malignant mesenchymal tumours otherthan angiosarcoma may have cytogenet-ic aberrations similar to those of soft tis-sue tumours {513, 1812}.

CarcinosarcomaThis neoplasm is defined as a malignanttumour containing an intimate mixture ofcarcinomatous (either hepatocellular orcholangiocellular) and sarcomatous ele-ments; such lesions have also beencalled ‘malignant mixed tumour’ of theliver. Carcinosarcoma should be distin-guished from carcinomas with foci ofspindled epithelial cells and from the raretrue ‘collision’ tumours.

Fig. 8.73 Angiosarcoma. A Closely packed elongated tumour cells. B Pink-brown granular deposits of Thorotrast in a portal area adjacent to an angiosarcoma.BA

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199Secondary tumours

DefinitionMalignant neoplasms metastasized tothe liver from extrahepatic primarytumours.

EpidemiologyIn Europe and North America, metas-tases predominate over primary hepatictumours in a ratio of 40:1 {130, 1517}. InJapan the ratio is 2.6:1 {1517}. In South-East Asia and sub-Saharan Africa, pri-mary hepatic tumours are more commonthan metastases {1909} owing to the highincidence of hepatocellular carcinoma, ashorter life span (common extrahepaticcarcinomas affect older age groups) andthe low incidence of certain tumour types(e.g. carcinomas of the lung and col-orectum). Autopsy studies in the USAand Japan have shown that about 40%of patients with extrahepatic cancer havehepatic metastases {351, 1517}.

AetiopathogenesisThe liver has a rich systemic (arterial)and portal (venous) blood supply, pro-viding a potentially abundant source ofcirculating neoplastic cells. Circulatingtumour cell arrest is controlled by Kupffercells in the sinusoids {881, 121} and maybe enhanced by growth factors such astransforming growth factor alpha (TGFα){385}, tumour necrosis factor (TNF){1431}, and insulin-like growth factor-1(IGF-1) {1091}. As tumour depositsenlarge, they induce angiogenesis usingnative sinusoidal endothelium; thisenhances their chances of survival and isoften macroscopically evident {1919}.Most metastases from unpaired abdomi-nal organs reach the liver via the portalvein, and from other sites via the systemicarterial circulation. Lymphatic spread isless common and extension to the livervia the peritoneal fluid is rare {351}. Cirrhosis provides some relative protec-tion against seeding by secondarytumours {1983, 1211}. It has also beensuggested that metastasis is rare in fattylivers {676}, but excess alcohol con-sumption apparently enhances hepaticmetastases {1140}.

In the majority of cases, metastases tothe liver are a manifestation of systemic,disseminated disease. Colorectal carci-noma, neuroendocrine tumours, andrenal cell carcinoma are exceptions asthese neoplasms sometimes produceisolated, even solitary deposits {1517}.

Origin of metastasesThe majority of secondary liver neo-plasms are carcinomas, involvement bylymphomas is next and sarcomas areuncommon. The order of frequency byprimary site in Western populations is:upper gastrointestinal tract (stomach,

gallbladder, pancreas): 44-78%; colon:56-58%; lung 42-43%; breast 52-53%;oesophagus 30-32% and genito-urinaryorgans 24-38% {130, 1517, 351}.Carcinomas of the prostate and theovaries preferentially spread to the lymphnodes and the spine, and to the peri-toneal cavity, respectively. Hodgkin and non-Hodgkin lymphomasmay involve the liver in up to 20% ofcases on presentation and 55% at autop-sy {1620, 826}. Sarcomas are much lesscommon but 6% had hepatic metastasesat presentation (mostly intra-abdominalleiomyosarcomas) in one study {833},

P.P. AnthonyP. DeMatosSecondary tumours of the liver

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FEFig. 8.74 Secondary tumours in the liver. A Metastatic colon carcinoma showing umbilication and hyper-emic borders. B Metastatic small cell carcinoma of lung forming inumerable small nodules. C, D Metastaticlarge intestinal carcinoma, cut surfaces. E Metastatic gastric adenocarcinoma, cut surface. F A metastasislies adjacent to a Zahn infarct.

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while 34% had hepatic metastases atautopsy in another {1517}.In a study of randomly selected liverbiopsies from England and Wales {852},the commonest histological type ofmetastasis was adenocarcinoma (39%),followed by carcinoma not otherwisespecified (36%); the rest were undifferen-tiated small cell carcinoma, other specialtypes of carcinoma, and lymphomas.

Clinical featuresSymptoms and signsHepatic metastases produce clinicalmanifestations in about two-thirds ofcases and they generally reveal them-selves through symptoms referable to theliver. Afflicted patients often present withascites, hepatomegaly or abdominal full-

ness, hepatic pain, jaundice, anorexia,and weight loss. Constitutional symp-toms, such as malaise, fatigue, and fevermay be present. On examination, nod-ules or a mass are felt in up to 50% of thecases, and a friction bruit may be heardon auscultation. Unfortunately, sympto-matic presentation is associated withbulky, rapidly progressive tumours with apoor prognosis {2035}. Rarely, patients present with fulminanthepatic failure, obstructive jaundice, orintraperitoneal haemorrhage. Function-ing neuroendocrine tumours produce syn-dromes of hormonal excess. ‘Carcino-matous cirrhosis’ with jaundice, ascites,and bleeding varices due to diffuse infil-tration of the liver, usually by metastaticbreast carcinoma, has been described{174}.

Laboratory studies The alkaline phosphatase (ALP) andserum glutamic-oxaloacetic transami-nase (SGOT) levels, although non-spe-cific, are elevated in approximately 80%and 67% of patients respectively, andmost likely represent the effects of hepat-ic parenchymal infiltration by tumour andof generalized wasting. Elevated lacticdehydrogenase (LDH) levels are relative-ly specific for the presence of metastatic

melanoma. Tests of synthetic function,e.g. serum albumin levels and the pro-thrombin time, may be normal despiteextensive metastatic involvement. Alpha-fetoprotein (AFP) levels may be slightly tomoderately elevated but very high con-centrations are more consistent with adiagnosis of hepatocellular carcinoma{904}. Carcinoembryonic antigen (CEA)levels, which are raised in as many as90% of patients with metastases fromcolorectal carcinoma, can be useful inmonitoring patients after primary tumourresection. However, CEA levels do notcorrelate well with prognosis {2043,1821}.

Imaging Ultrasound (US) can identify tumoursmeasuring 1-2 cm in size, can differenti-ate solid from cystic lesions, and provideguidance for percutaneous needle biop-sy. However, it provides poor anatomicaldefinition and frequently misses smallerlesions.Computed tomography (CT), using bothcontrasted and non-contrasted images,can also serve as a screening tool. Theadministration of intravenous contrastpermits the detection of tumours as smallas 0.5 cm in diameter {1763}. Most meta-stases display decreased vascularity incomparison to the surrounding hepaticparenchyma and appear as hypodensedefects. Tumours that are hypervascular(e.g. melanoma, carcinoids and somebreast cancers) or calcified (e.g. colorec-tal carcinoma) are better delineated bynoncontrast views.Magnetic resonance imaging (MRI) ismore sensitive than CT in the detection ofhepatic tumours and can demonstrateadditional lesions, too small to be seenon CT.Positron emission tomography (PET) candetect metastatic disease in the liver andelsewhere. Using 2-(18)fluoro-2-deoxy-D-glucose (F-18 FDG), a radiolabeledglucose analogue, PET highlights meta-bolically active tissues. Through co-reg-istration with anatomical studies like CTor MRI, viable malignant tumours can bedifferentiated from benign or necroticlesions {54}. CT arterial portography performed pre-operatively, and intraoperative ultra-sound are associated with the highestsensitivities {1796}. The former is capa-ble of detecting lesions as small as 15 mm, although a false positive rate of

BAFig. 8.75 Metastatic tubular adenocarcinoma from the stomach. A Haematoxylin and eosin. B Intraluminaldiastase-resistant PAS positive mucin.

BAFig. 8.76 Metastatic colorectal carcinoma. A Tumour is necrotic and cell type is typically columnar. B Necrosis may result in calcification.

Fig. 8.77 Metastatic breast carcinoma.

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201Secondary tumours

17% has been reported {1795}. Its suc-cess relies on the fact that tumours arenot fed by portal vein blood, so thatmetastases appear as filling defects. Thelatter, capable of detecting lesions 2-4mm in diameter delineates the anatomi-cal location of tumours in relationship tomajor vascular and biliary structures andprovides guidance for intraoperativeneedle biopsies. It is the definitive step indetermining resectability at the time ofexploratory laparotomy or laparoscopy.Angiography use has declined in recentyears. It remains useful for defining vas-cular anatomy for planned hepatic resec-tions, selective chemotherapy, chemo-embolization, or devascularization pro-cedures, for assessing whether there ismetastatic involvement of the portalvenous system and/or hepatic veins, andfor differentiating between benign vascu-lar lesions, such as haemangiomas andmetastases, when other imaging studieshave yielded equivocal results.

MacroscopyThe distribution of metastases from col-orectal carcinoma was found to behomogenous, regardless of the primarysite of origin {1695} but in another study,it was suggested that right sided cancerspredominantly metastasize to the rightlobe of the liver and left sided cancers toboth lobes {1749}.Metastases are nearly always multinodu-lar or diffusely infiltrative, but may rarelybe solitary and massive (e.g. from colo-rectal and renal cell carcinomas).Umbilication (a central depression on thesurface of a metastatic deposit) is due tonecrosis or scarring and is typical of anadenocarcinoma from stomach, pan-

creas or colorectum. A vascular rimaround the periphery is often seen.Highly mucin secreting adenocarcino-mas appear as glistening, gelatinousmasses whilst well differentiated kera-tinizing squamous cell carcinomas aregranular. Metastatic carcinoid tumourscan form pseudocysts {401}. Haemor-rhagic secondary deposits suggestangiosarcoma, choriocarcinoma, carci-noma of thyroid or kidney, neuroen-docrine tumour, or vascular leiomyosar-coma. Some diffusely infiltrating carcino-mas (e.g. small cell carcinoma), lym-phomas and sarcomas may have a soft,opaque ‘fish flesh’ appearance. Meta-static breast carcinoma in particular canproduce an intensely fibrous, granularliver (‘carcinomatous cirrhosis’) eitherbefore {174} or after {1693} treatment. Calcification of secondary deposits is afeature of colorectal carcinoma but it isseldom excessive and has no effect onprognosis {653}. Metastatic melanoma isoften, but not always, of a brown-blackcolour. Secondary tumours may appearin the liver long after the removal of theprimary.

HistopathologyLiver biopsy samples can be obtained bypercutaneous or transjugular routes withor without imaging techniques for guid-ance, as a wedge during laparotomy, ora fine needle can be used to aspiratematerial for cytology. Each of these meth-ods has advantages and drawbacks buta guided percutaneous needle biopsyproducing a core of liver for histology isthe one most frequently used. It pro-duces a tissue sample that is usuallyadequate for all purposes, including theuse of special stains, immunohistochem-istry and molecular biological tech-niques. Touch preparations for cytologycan also be prepared from needle coresbefore fixation and may provide aninstant diagnosis {1523}.

Differential diagnosisHepatocellular carcinoma can usually bedistinguished from metastatic tumours byits trabecular structure, sinusoids, lack ofstroma, bile production, absence ofmucin secretion, and the demonstrationof bile canaliculi by polyclonal CEA anti-sera, which is specific for a liver cell ori-gin. Other useful immunophenotypic fea-tures in this differentiation are the pres-ence of liver export proteins (albumin,fibrinogen, alpha-1-antitrypsin), the cyto-keratin pattern, and the expression ofHep Par 1 antigen {1046}. Metastatictumours that often mimic hepatocellularcarcinoma are adrenal cortical and renalcell carcinomas. Amelanotic melanomamay also cause difficulties but it is easilyidentified by positive immunostaining forS100 protein and HMB45 .The distinction between primary cholan-giocarcinoma and metastatic adenocar-

Fig. 8.79 Systemic non-Hodgkin lymphoma involv-ing the liver.

Fig. 8.78 Metastatic islet cell carcinoma of pancreas. A Haematoxylin and eosin. B Somatostatin immunoreactivity.

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cinomas is much more difficult and maybe impossible {351}. Cholangiocarcino-ma may take on any of the histologicalpatterns of an adenocarcinoma; it is usu-ally tubular but may be mucinous, signet-ring, papillary, cystic, or undifferentiated.Mucin secretion and production of CEAare nearly always demonstrable in bothprimary and secondary adenocarcino-mas. Metastases from many sites formsimilar patterns. However, small tubularor tubulo-papillary glands frequentlyderive from the stomach, gallbladderand extrahepatic biliary tree, and asignet-ring cell appearance suggests agastric primary. Perhaps the easiest pat-tern to recognize as metastatic in originis that exhibited by adenocarcinomas ofthe colon and rectum, which nearlyalways show glands of variable size andshape that are lined by tall columnarcells and contain debris within the lumi-na. Metastases from the colorectum fre-quently have well defined edges where-as those from other glandular sites tendto be more diffuse. Colorectal metas-tases are also frequently necrotic andmay show calcification {653}. The presence of carcinoma-in-situ inintrahepatic bile ducts in the vicinity of anadenocarcinoma is evidence that it is acholangiocarcinoma. However, this maybe mimicked by intrabiliary ductal growthof metastatic colonic adenocarcinoma{1593}. Analysis of cytokeratin expres-sion may be useful in the distinction of

primary and metastatic gastrointestinaladenocarcinomas. The former expresscytokeratins 7 and 19 but not 20, where-as the latter are negative for 7 and posi-tive for 20 {1141}. Carcinoma of the breast often producesa diffuse sinusoidal infiltrate that onimaging studies may mimic cirrhosisand, indeed, may be associated withsplenomegaly, ascites and oesophagealvarices {174}; sclerosis following sys-temic chemotherapy may exaggeratethis effect. Metastases from the breastmay be identified by the combined use ofzinc-α2-glycoprotein, gross cystic dis-ease fluid protein 15 and oestrogenreceptor {283}. However, occult breastcarcinoma presenting with metastases israre and most patients with liver involve-ment have a past history of a primarytumour.Most hepatic metastases from the lung inclinical practice are undifferentiatedsmall cell carcinomas, characteristicallyproducing an enlarged liver due to dif-fuse or miliary spread. The primarytumour may still be small, asymptomaticand undetected. Squamous cell andadenocarcinomas will metastasize to theliver but their existence is usually knownalready. The same applies to squamouscell carcinomas of the oesophagus andcervix. Squamous cell carcinomas of thehead and neck seldom involve the liver.Neuroendocrine/islet cell/carcinoid tu-mours are easily identified by their

organoid nesting pattern, uniform cytol-ogy and vascularity, and positiveimmunostaining for chromogranin, syn-aptophysin and neuron specific enolase;islet cell tumours also produce specifichormones such as insulin, glucagon,gastrin, vasoactive intestinal peptide andsomatostatin, which either give rise toclinical syndromes or can be demon-strated in the blood or tumour tissue. Most sarcomas that metastasize to theliver are gastrointestinal stromal tumoursthat are positive for CD34 and c-kit, orleiomyosarcomas of the uterus that maybe positive for desmin or muscle-specif-ic actin. Some carcinomas, notably of thekidney, may be sarcomatoid in their mor-phology. Many haematological malignancies, e.g.leukaemias, myeloproliferative disordersand both Hodgkin and non-Hodgkin lym-phomas, involve the liver. Leukaemiastend to produce diffuse sinusoidal infiltrates. Hodgkin and high-grade non-Hodgkin lymphomas produce tumour-like masses, while low-grade non-Hodgkin lymphomas produce diffuseportal infiltrates.Rare secondary tumours include thosefrom the thyroid, prostate, and gonads.The diagnosis can be confirmed by theimmunohistochemical demonstration ofthyroglobulin, prostate specific antigenand AFP and βHCG, respectively.A triad of histological features, namelyproliferating bile ducts, leukocytes andfocal sinusoidal dilatation, is found in theliver adjacent to space-occupying le-sions. Their presence in a core biopsysuggests the possibility of a metastaticdeposit missed by the biopsy needle.Three lesions, bile duct adenoma, scle-rosed haemangioma, and larval granulo-ma may resemble metastatic tumours atlaparotomy.

PrognosisIn most cases, disseminated disease ispresent which precludes surgical inter-vention. Due to recent improvements inimaging techniques, more metastaticcarcinomas are being diagnosed early,providing the possibility of surgicalresection in a greater number of patients.When curative resection is feasible, 5-year survival can be as high as 40%;without surgical therapy, median sur-vivals of less than 12 months should beexpected {1817}.

Fig. 8.80 Typical histological changes adjacent to space occupying liver lesions: sinusoidal dilatation, leuko-cyte infiltration, and bile-ductular proliferation.

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Tumours of the Liver and Intrahepatic Bile Ducts · CHAPTER 8 Tumours of the Liver and Intrahepatic...

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Transcript of Tumours of the Liver and Intrahepatic Bile Ducts · CHAPTER 8 Tumours of the Liver and Intrahepatic...