107

HYDATID DISEASEBy JAMES A. JENKINS

Dunedin, N.Z.

Hydatid* disease in man may present a simplesurgical problem, or it may be as impossible oferadication as a widely metastasized malignanttumour. The life cycle of the parasite is fullydescribed in textbooks on surgery and in thispaper certain less known aspects only are dealtwith. Methods of prevention are also excluded,though it should be widely known that there is nodisease that so readily lends itself to completeeradication. Infestation occurs in early childhood.There is little evidence that infection arises later inlife or, if it does, one must assume that it isusually overcome by the host.The hexacanth embryo on emerging from the

hydatid ovum is an actively motile structure ofabout 25 microns. It probably reaches the liver viathe portal circulation within a few hours of theeggs being swallowed. If several ova are swallowedmultiple primary cysts may be formed (6o per cent.of cases). The embryo may pass the filter of theportal circulation and lodge in the lungs, givingrise to a ' primaryv' lung cyst. If it succeeds inpassing the lungs a primary peripheral cyst maydevelop in any structure of the body. Peripheralcysts occur in muscles in about 4 per cent., in bonein 2 per cent. and in the kidneys in 2 per cent. ofcases. It should be emphasized however thatbetween 60 and 70 per cent. of primary cystsoccur in the liver, the lungs being next with about23 per cent. If a primary cyst disseminates itscontents to other parts of the body the results areknown as ' secondary' cysts. This disseminationmay be by way of the blood stream or across thepleural or peritoneal cavities. The liver shouldalways be carefully examined for a primary cystif cysts are found elsewhere.When the hexacanth embryo reaches its destina-

tion it develops into a small vesicle and this, actingas a foreign body to the host, causes a cellular re-action in the tissues which later becomes a fibrousmembrane-the pericyst. Within the pericyst thevesicle gradually develops two layers which formthe wall of the hydatid cyst proper. The outerlayer, the ectocyst, laminated membrane orchitinous layer, forms the bulk of the cyst wallwhilst the inner layer, the endocyst, parenchy-matous or germinal layer, is a structure of micro-

* From the Greek Swcop, water; vSaroesr, watery,like water, referring to the contents of the cysts.

scopic thinness which produces brood capsuleswith their scolices and perhaps daughter cysts.Not until the cyst reaches a certain size are broodcapsules formed. These tiny structures developscolices, some of which become free in the clearfluid content of the cyst. The resemblance of thebrood capsules and scolices to fine sand has led tothe use of the term ' hydatid sand.'

Scolices and brood capsules are capable of de-veloping into fully formed hydatid Cysts if theygain entrance to serouQ cavities, wound surfaces orthe blood stleam. It is unfortunate that the term' sterile cyst' has crept into the literature as allcysts are potentially dangerous in regard to powersof dissemination. A' sterile cyst' is a univesicularcyst as opposed to a cyst containing daughter cysts,and it is ' sterile ' only in the sense that it has notyet produced daughter cysts, but its capacity forspreading the disease widely is only too oftendemonstrated in countries where hydatids abound.If the cyst is threatened by trauma, lack of nourish-ment, the irritation of infection in the pericyst,leakage of some of its contents into an adjacent ductor cavity, or leakage of some foreign substance suchas bile into the cyst, then its continued survival issafeguarded by the formation of daughter cysts.These daughter cysts, like the scolices and broodcapsules, are capable of growing into fully formedhydatid cysts. The daughter cysts vary greatly insize and number, but are usually from ~ to 2 in.in diameter. They are replicas of the mother cyst.The pericyst plays a very important part in the

life of the hydatid. Through it the cyst receivesnourishment but, as time goes by, the pericyst re-action which represents the host's tissue responseto a foreign body becomes greater and the nourish-ment of the cyst suffers. Degenerative changesand calcification are commonly found in the wallof the pericyst. Tissues such as brain and spinalcord fail to form pericysts. It is often badlyformed in the lung. It is important to rememberthat the pericyst or adventitious layer is part of thehost and attempts at its surgical removal lead todisaster unless it is in a free and accessible position,where it can be removed together with the organcontaining the cyst (such as the kidney or lobe ofa lung). Where the pericyst is lacking, the hydatidthrives on the nourishment it obtains from thesurrounding tissue fluid.

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The cyst may' die,' becoming a pultaceous masssurrounded by a thick and often calcified pericyst.A calcified, puckered cicatrix may be all that re-mains of a mother cyst. It is very difficult to becertain in the ' dead cyst' that there are no viableelements.

In most cases the hydatid continues to grow untilspace-occupying symptoms (pressure effects, de-formity, pain), infection, leakage (into a duct suchas a bronchus or bile duct, or to a serous surface)or toxic manifestations from the absorption ofantigens bring the patient up for investigation. Itis a not infrequent occurrence to find a cyst whenoperating for other conditions, or at post mortem,there being no past symptoms referable to thehydatid.

Suppuration arises most commonly in cystsclosely associated with ducts such as the intra-hepatic bile ducts, the bronchi, or the intestinal orurinary tract. A cyst in a conspicuous site maybring the patient at an early stage. For example agirl of 22 presented herself with a prominentcystic swelling i in. in diameter in the lower partof the posterior triangle of the neck. It was foundon removal to be a hydatid cyst. There was noevidence of cysts elsewhere. Cysts in the rightlobe of the liver may reach enormous proportionsbefore the patient is aware that anything is wrong.Leakage from a cyst causes acute anaphylacticsymptoms whilst its sudden rupture into a serouscavity or duct, or the disaster of intravascularrupture may produce an acute emergency. Cystsin confined areas such as the spinal canal, craniumor pelvis may early produce marked symptoms bypressure on neighbouring structures.

Rate of Growth of Primary Hydatid CystsThe rate of growth varies enormously and the

' soil' appears to be the determining factor. Thevascular supply of the host's tissues is of para-mount importance. The fibrous pericyst eventuallysuffers thickening and degeneration which limitsgrowth and excludes from the cyst the nourish-ment required. Limitation of expansion by thedensity and fixity of surrounding structures mayalso check its rate of growth. The most rapidgrowth is seen in the case of liver cysts in youngchildren.

Case A.-Illustrating rapid rate of growth in a

liver cyst.A child aged three years was admitted to the

Dunedin Hospital in August, 1934, on account ofdistension of the abdomen. The mother statedthat she had noticed this swelling only one monthpreviously and that it was increasing. The childhad not shown any discomfort. On examinationthe abdomen was grossly distended by a tumour

which filled the epigastrium and right hypo-chondrium. It appeared to be continuous withthe liver and extended to well below the umbilicus.It was smooth, firm and elastic. Both hydatidcomplement fixation and Casoni reactions werenegative. Eosinophilia, 7 per cent.At operation a tense cyst about 6 inches in

diameter was found within the right lobe of theliver. It proved possible to suture the parietalperitoneum to a fibrosed area in the liver where thecyst approached the surface. The cyst was thenaspirated and the membranes were removedapparently intact. There were no daughter cysts.Formalin solution was not used. The cavitv wasfilled with saline and the opening in the pericystclosed without drainage. Convalescence wassatisfactory there being no infection in the cavityand no leakage of bile. The hydatid complementfixation test became strongly positive three weeksafter operation. The Casoni test remainednegative.At the age of four years the child was admitted

for tonsillectomy and was reported as being wellapart from the throat condition. At the age of fiveyears she was admitted with otitis media and therecord states then that the liver was enlarged two-thirds down to the umbilical plane.At the age of six years she was readmitted under

my care. Her mother had noted an abdominalswelling and also the fact that the ribs on the rightside appeared to be pushed out. The hydatidcomplement fixation and Casoni tests were

negative. The abdominal condition was very likethat seen three years previously. The right lowerribs showed a distinct bulge (Fig. i).At operation (I.4.37) there were no adhesions

between the liver and the parietal peritoneum, andthe abdominal wall was closed over an iodinegauze pack placed over the surface of the liver.On I6.4.37, part of the pack was removed and a

cyst was aspirated. After it had been emptied theremainder of the gauze was removed. The hydatidmembranes were lifted out and the pericyst cavitythoroughly irrigated with saline. There were no

daughter cysts present. A tube was inserted todrain the cavity. Again no formalin was used.Apart from some pulmonary complication con-valescence was 'uneventful and the sinus healedwithin three months. She has been the subject ofa careful follow up and to date there is no sign ofrecurrence.

Comment. This child, when aged three years,had a cyst 5 to 6 in. in diameter. The rate ofgrowth appears to have been abnormally rapidbut shows what may occur. The omission to pseformalin was a mistake. It is probably the mosteffective lethal agent we have for scolices-2 percent. formalin killing these within five minutes.

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JENKINS: Hydatid Disease

My reason for not using it at this period was an

Vnhappy experience of its great toxicity bothlocally on the tissues and generally throughabsorption. It has to be used with great care. Itshould never be injected into lung cysts, or intoliver cysts if there is the possibility of communica-tion with a large bile duct. It can be safely swabbedover the interior of the pericyst on occasions wheninjection into the cyst is not considered safe. It isprobably of little use when a mother cyst is packedwith daughter cysts, as it has no opportunity ofmaking contact with the contained scolices.

The hlung appears to be the next most favourablesite for rapid growth, but symptoms or complica-tions caused by the cyst are liable to bring thepatient to treatment relatively earlier than in thecase of liver cysts. Cysts of 3-4 in. in diameter arenot uncommon in children under the age of eightyears, as in the following example.

Case B.-Illustrating rate of growth in the lung.A child, eight years of age, was admitted to

hospital on 24.11.42 with a history of pain in theright side of the chest, and of slight cough forii weeks. A diagnosis of pleurisy had originallybeen made, but X-rays (Fig. 2) disclosed a largecyst in the right lung. On 30.11.42, under localanaesthesia, 3 in. of the eighth and ninth ribs wereremoved in the posterior axillary line. The pleurawas not adherent. Through a small opening steriletalc was smeared on the pleural surface over thecyst, an extrapleural iodine gauze plug wasapplied and the wound tightly closed. On10.12.42, under local anaesthesia, the wound wasreopened, and the cyst removed. There was nobronchial communication. A tube was placed inthe resulting cavity. The patient was dischargedon 22.1.43, healed and symptomless.

Comment. Some surgeons prefer general an-aesthesia to lessen the risk of anaphylaxis fromspill of hydatid fluid. When treated in two stagesthe simple peripheral cyst with a non-adherentpleura presents usually little difficulty. Openingof the pleural cavity is unnecessary for a cystpresenting on the lung surface, as a firm iodinegauze pack left in the extrapleural space producessatisfactory adhesions which enable the pleura tobe incised safely at a second stage.

Secondary cysts in the peritoneal cavity do notappear to grow as rapidly as primary cysts in othersituations. Multiple abdominal cysts arising fromleakage from a liver cyst probably commence theirgrowth in late childhood or early adult life, whenrupture is most common. The resistance of thehost's tissues, ' the soil,' is fortunately greater, andit' is also possible that the second generation ofcysts is less active than the first.The rate of growth in bone is difficult to assess

as the cyst undergoes a marked change in its modeof growth in this structure. Following the line ofleast resistance along the interstices of the can-cellous tissue and the medullary canal, extracysticbudding occurs and a rib or a long bone may be-come involved from end to end by this exogenousgrowth. The medullary cavity and cancelloustissue become riddled by thousands of cysts, vary-ing in size from a pin's head to a cyst a third of aninch in diameter.

In general the rate of growth of cysts in allorgans gets progressively slower as the age of thecyst increases. The important part the pericystplays in food supply to the cyst has already beenmentioned. Many cases, undoubtedly childhoodinfections, come to operation for the first time inmiddle age when the cyst has found its environ-ment less favourable owing to the onset of somecofmplication.Peculiarities of Growth in Various OrgansThe organ or structure in which a hydatid cyst is

lodged exerts a marked effect on the developmentof the cyst, its contents and the liability to com-plications. A brief survey is here given of theoutstanding characteristics of cysts in varioussituations.

HYDATIDS OF THE LIVERBetween 6o and 70 per cent. of all cysts occur in

the liver. This is to be expected when the methodof spread and the life history. of the hydatid areconsidered. The right lobe being larger than theleft is correspondingly more commonly involved.The cyst usually continues to grow until one ormore of the following complications bring thepatient for treatment.

I. Pressure. This may cause (a) deformity,either a marked bulging of the abdominal wall ora deformity of the overlying chest wall (Fig. i). (b)Pain which may be localized to this area orreferred to the shoulder owing to involvement ofthe diaphragm. (c) Gastro-intestinal symptoms(Fig. 5). (d) Respiratory and cardiac embarrass-ment and signs of obstruction to the portal veinor inferior vena cava.

2. Infection. Infection causes a subacute orchronic liver abscess. Due to erosion of bile ducts,infection is a common occurrence in old standingcysts in middle-aged and elderly people. Pain andcachexia may be a marked feature. Depending onthe site of the hydatid cyst the abscess may beentirely intrahepatic or may form a subphreniccollection. Secondary septic involvement of thepleural cavity is not uncommon.

Case C.-Illustrating pressure symptoms andgrave infection.

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A woman, aged 68, was seen on 3.3.47 com-plaining of pain in the right side of the abdomenof some months' duration, and of marked loss ofweight and strength. She looked desperately illand was extremely breathless, with a rapid weakpulse. The apex beat was in the fourth intercostalspace in the left mid-axillary line, the heart beingpushed over and rotated. A large mass filled theright abdomen down to the level of the anteriorsuperior spine of the ilium. The legs wereoedematous and there was evidence of markedvenous back pressure. Both Casoni and hydatidcomplement fixation tests were strongly positive.In view of her inability to lie down and her veryprecarious physical condition, the cyst was exposedunder local anaesthesia by an incision below theright costal margin. Fortunately the liver andcyst were adherent to the abdominal wall at thispoint. A small incision was made through the cystwall to relieve tension, and gradually two to threegallons of pus and hydatid debris and daughtereysts were allowed to escape. A week later when*her condition had improved the incision was ex-tended under local anaesthesia and the remains ofmembrane and daughter cysts were removed. Thehuge cavity extended up to the third rib, and thedislocated heart could be felt impinging on itsmedial surface. The cavity gradually shrank andthe wound was healed in 3j months' time. Allevidence of pressure symptoms disappeared, asshown by the return of the heart to normalposition, and the loss of venous congestion andoedema. All signs of ' hydatid cachexia' alsodisappeared.

3. Secondary lung complications. The cyst maybulge through the diaphragm which eventuallygives way, the lung now forming the upperboundary of the cyst. The opening in thediaphragm may not be large, but there may be anextensive cavity both above and below it.

Case D.-Illustrating secondary lung complica-tions.A male, aged 54 years, was admitted on I6.1 1.42

complaining of pain in the right side of his chest,cough and temperature of eight weeks' duration.He stated that he had had pleurisy and pneu-monia seven years previously. He had felt veryill during the past two weeks. The pleural cavityon the right side had been aspirated by his doctorand purulent fluid withdrawn.

Operation, 19.11.42. A rib was resected and alarge cavity filled with pus and hydatid debris anddaughter cysts was found occupying the lower partof the right pleural cavity. There was an openingthrough the diaphragm ix in. in diameter com-municating with a hydatid cyst in the dome of theliver. After removal of all hydatid membrane and

daughter cysts, 2 per cent. formalin was swabbedover the wall of the cavity and a drain was inserted.He was discharged healed on 23.3.43.When seen on 8.10.43 there was a small sub-

cutaneous cyst in the chest wall in front of theoperation incision. Hydatid complement fixationtests were negative.He was readmitted on 15.8.46 for treatment of

this cyst which had steadily grown and was nowcausing pain. Examination revealed a tense cysticswelling 31 in. by 21 in. centred about the mid-axillary line in the chest wall. The hydatid com-plement fixation test was strongly positive. Awell marked hydatid thrill was present. Thisthrill was felt as a sustained coarse vibration per-sisting after firm percussion.At the second operation there were many

daughter cysts present. The adjacent rib andintercostal muscles were infiltrated by hydatids andall involved tissue was removed en bloc. A furthercyst was found below the diaphragm and wasemptied. He was discharged healed on 1.10.46,and when seen in i947 his hydatid complementfixation and Casoni tests were both still stronglvpositive.

It can be readily seen that it is but a short stepfrom this condition to a lung abscess whichmay rupture into a bronchus, and should at thesame time a biliary communication be present, ahepato-bronchial fistula is likely to result. Largequantities of bile may be expectorated by a patientsuffering from this condition.

Case E.-Illustrating secondary lung complica-tions.A male, aged 45 years, was admitted to the

medical wards on 2I.1.37 with a history of coughand weakness over a period of seven years. Hehad coughed up blood-stained sputum and hadrun irregular temperatures for the past 14 months.Past history. In 1916 he was operated on else-where for a hydatid of the liver, by a trans-thoracic approach, and an empyema'had followed.There had been further operations of which nodetails are available. Examination showed grossscarring and collapse of the right lower chest.The Casoni test was strongly positive both forimmediate and delayed reaction. The hydatidcomplement fixation reaction was negative.Bronchograms (Fig. 3) disclosed the pressureeffect of the cyst on the lower lobe bronchi.He was readmitted on 13.7.37 and transferred

to the surgical wards. He was very thin, cachectic,and in poor condition for surgery. Further X-rayinvestigation confirmed the presence of a cyst at thebase of the right lung (Fig. 4). Operation wasperformed under local anaesthesia and a largecavity containing pus and -hydatid debris was

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found. Free drainage was established. Theopenings of many bronchi could be seen, and thesewere cauterized.On 24.8.37 a phrenic avulsion was carried out.

He was then transferred to a convalescent home,the fistulae still being open. He was readmitted ayear later under another surgical service with per-sistent bronchial fistulae. Thiersch grafts of skinfrom the arm were applied to the walls of theintrathoracic cavity, without benefit. When re-admitted on I8.2.39, under my care, his conditionwas unchanged. Lipiodol injected into the sinuspassed directly into the main lower lobe bronchus.All the lower lobe bronchi showed distortion anddilatation.

Operation, 28.2.39. Extensive rib resectionwas carried out over the right lower chest. Thecavity was freely exposed, the whole lining mem-brane was dissected off with the electric cuttingcurrent, and an attempt was made to close theopening into the bronchi by suture. The over-lying soft tissues of the chest wall were collapseddown to obliterate the cavity, and were maintainedby pressure in this position. He was dischargedon 6.4.39, completely healed.

Comment. The cyst in the base of the rightlung had presumably originated from the livercyst operated on 20 years previously. Bronchialepithelium had spread on to the inner wall of thepericyst. Section of the wall removed at operationshowed it to be lined by both squamous epitheliumand bronchial mucous membrane. It was obviousthat the epithelial lining would prevent oblitera-tion of this cavity. A case presenting grossbronchial dilatation and deformity would now,probably be better dealt with by lobectomy, butthe Schede operation combined with excision ofthe epithelial lining and closure of bronchiyielded a satisfactory result.

4. Anaphylactic phenomena. Anaphylacticphenomena may be mild, or they may be sointense as to produce coma and death. Diagnosticaspiration of cysts has in the past been a fertilesource of both acute anaphylaxis and of dissemina-tion of the disease.

5. Sudden rupture. A sudden rupture into theperitoneal cavity is a rare event but it may causeacute abdominal symptoms. That it may alsocause little upset is evidenced by the presence ofmultiple cysts scattered throughout the abdomenin cases giving no history of rupture.

6. Obstruction of the biliary passages. Obstruc-tion of the biliary passages by daughter cysts occurstoo often in endemic areas to be ignored as a causeof acute biliary colic or obstructive jaundice.

7. Death of cyst. Excessive fibrous reaction inthe pericyst, leakage, or low grade infection maycause death of the cyst and this is followed fre-

quently by calcification of the pericyst. Thecontent of the cyst becomes pultaceous, pro-gressively inspissated, and later calcified. Suchcalcified cysts are often discovered by accident inroutine X-rays (Fig. 5).

Case F.-Illustrating excessive fibrous reactionin pericyst.

In a female, aged i8 years, hydatid cysts in theliver were discovered during the course of anX-ray examination of the spine and she was ad-mitted to hospital on 8.1.43 for further investiga-tion. She appeared to be a healthy young womanand the only abnormality on physical examinationwas some questionable fullness below the costalmargin on each side. Hydatid complementfixation and Casoni tests were strongly positive.Further X-rays showed elevation of the right andleft sides of the diaphragm, some calcification inthe epigastrium and the evidence of a cyst belowthe right lobe of the liver. A barium meal showedpressure of the cyst on the fundus of the stomachand the outline of the cyst could be seen below thelevel of the cupola (Fig. 6).

Operation in January 1943 confirmed thesefindings. At a first stage the abdomen wasopened and the large cyst on the left side was dealtwith. After formalization and evacuation it wasdrained through the left upper abdomen. Thepericyst was about a quarter of an inch thick, rigidand non-collapsible. A small cyst was foundattached to the liver edge and was excised. Anold calcified scar occupied the anterior surface ofthe right lobe of the liver. Further cysts werepalpated, one in the liver below the dome of thediaphragm on the right side, and another belowthe anterior edge of the liver filling the right flank.

* Three weeks after operation drainage becameunsatisfactory, the patient becoming toxic andrunning a high temperature. There were signs ofleft basal consolidation. The left subphrenicspace was entered after rib resection and exclusionof the pleura, and a collection of pus in the spacepreviously occupied by the cyst was drained.Convalescence was uneventful. Three monthslater the right lobe of the liver was exposed througha Kocher's incision and after careful packing offand formalization, the cyst attached to the edge ofthe right lobe was emptied and most of the extrahepatic pericyst was excised. After resection of thecostal margin and elevation of the pleural reflectiona large cyst on the upper surface of the liver wasdealt with. Convalescence was uneventful.

Comment. This girl probably had two primarycysts, one represented by the calcified scar in theliver, and the other by the large cyst in the upperpart of the right lobe of the liver. I think theother cysts were probably secondary from rupture

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of the old parent cyst in the liver. The very thickand rigid pericyst found at the first operationformed a non-collapsible cavity under the leftdiaphragm, a cavity which was very slow inclosing.

8. ' Colossal peritoneal' cysts. Rupture of aparent liver cyst into the peritoneal cavity mayoccasionally give rise to colossal cysts that may bemistaken for ascites. Several such cases have beenrecorded (Barnett, 1927; Robinson and Deve(quoted by Barnett); Hutchinson, i890; andSyme, I909). In Barnett's case i gallons of hy-datid material were evacuated. The huge cavity islined by membrane, partly peritoneum and partlypericyst reaction, but nowhere are viscera seen.The lining membrane of the cavity completelyexcludes all recognizable intra-abdominal struc-tures. The theory advanced to account for thisparticular feature is that in the original rupture bileescapes, and the reaction to the chole-peritoneumis a plastic one that obliterates all peritonealrecesses.

Further Considerations of Liver CystsCysts in the liver tend to display certain charac-

teristics depending on (a) their position in theliver, (b) their relationship to other structures and(c) the intensity and duration of infection.

(a) Position in the liver. Cysts arising in thecentre of the right lobe of the liver are surroundedby liver tissue until, as growth proceeds, fibrouspericyst reaches the liver surface. It is thisintrahepatic type of cyst which often grows to verylarge proportions since it is well nourished and pro-tected, and apart from infection or other complica-tions it is unlikely to trouble the patient until ithas achieved a very considerable size. It is notuncommon to find a cyst 6-9 in. in diameterpresenting both on the anterior and inferior sur-faces of the liver. To the touch the presentingliver surface is tense and cystic, and the thinned-out liver tissue often 1 in. or less in thickness isfibrotic and relatively avascular, merging im-perceptibly into the pericvst. It is in this type ofcase that the liver as a whole feels diffusely en-larged, smooth and even when the abdomen isopened. Owing to the replacement of liver tissueby the cyst, hypertrophy of the organ occurs else-where and the left lobe of the liver becomesmarkedly enlarged. Small cysts up to the size ofa cricket ball may be easily overlooked if notoccupying a situation near to the surface of theliver.

Cysts lying in a peripheral position are corres-pondingly more easily recognized. If the cystcommences its growth near the liver edge or nearthe inferior surface it may reach several inches indiameter with but a small part of its wall actually in

liver tissue. It then projects into the peritonealcavity and in time becomes densely adherent tocontiguous structures such as the colon andomentum. Cysts on the under surface of the livermay cause displacement of the right kidney. Cystsarising near the diaphragm may cause markedelevation of this structure but care is necessary toexclude other causes.

Case G.-Illustrating elevation of the dia-phragm.A man, aged 50, was seen in February, I944,

with a large abdominal tumour filling the epigas-trium and right hypochondrium. He complainedof pain over the right shoulder and in the rightside of the chest. The mass in the abdomen wastense and cystic. The hydatid complement fixationtest was negative but the Casoni reaction wasstrongly positive. The radiograph showed a massin the upper abdomen and marked elevation ofthe right side of the diaphragm (Fig. 7).

Operation 11.2.44. Kocher's incision. Thecostal margin was resected, carefully avoiding thepleura which was stripped up. This providedfree exposure of the cyst which was then tappedand the fluid content replaced by 2 per cent.formalin. After a few minutes the formalin wasaspirated, the pericyst opened, and the membranesremoved. No daughter cysts were present. (De-tails of the technique employed to avoid spill aredealt with later.) The pericyst was then suturedto the rectus sheath in the line of the abdominalwall incision. The cavity was filled with salinecontaining 5 gm. of sulphanilamide powder, andthe skin incision was closed without drainage.Some days later there was a little fluid dischargeand evidence of mild infection, and a tube had tobe inserted into the liver cavity. Complete healingtook three months.Comment.-This uncomplicated liver cyst had

received no trauma from infection or bile leakage,nourishment had been satisfactory, and con-sequently no daughter cysts had been produced. Itis in this type of cyst that closure of the pericyst,after filling the cavity with saline, may result inearly healing. Bile leakage and infection, how-ever, frequently necessitate the later insertion of adrain-a simple procedure in that the pericyst isalready sutured to the abdominal incision. Sincethis operation the hydatid complement fixationhas remained suspiciously high, suggesting thepossibility of the presence of other cysts.

Multiple cysts are common in tlfe liver, two,three or four primary cysts being not infrequentlyfound. The scar or calcified remains of a primarycyst may be the stimulus that leads to a search ofthe abdomen for the growing daughter cysts thathave resulted from leakage of the parent cyst.

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(b) Relationship to other structures. Cysts inthe liver may bear very important relationship tostructures such as large bile ducts, main branchesof the portal venous system, the vena cava, etc.As the cyst expands it causes local pressure atrophyof the walls of these structures, and the pericystmay even disappear so that the hydatid membrane(ectocyst and endocyst) may actually form, over asmall area and probably for a limited time only,the wall of the duct. It is little to be wondered atthat when a cyst is opened, due to the great re-duction of tension that ensues, the membranesseparate from the pericyst and the duct lumenthen opens into the resulting cavity within the peri-cyst. This is the reason why bile so commonlyescapes into the cavity after the membranes havebeen removed. Such leakage may not occur forseveral days after operation. It also accounts forthe disastrous haemorrhage that may occuroccasionally (Jenkins 193I). It is the sameerosion of ducts that so commonly leads to ruptureof the cyst into the biliary tract with subsequentinfection within the pericyst, and similarly toescape of cyst contents into the hepatic ducts lead-ing to biliary obstruction by daughter cysts ormembrane. A similar leakage of cyst content intothe radicals of the vena cava may lead to hydatidembolism of the lungs.

(c) The intensity and duration of infection. Theintensity and duration of infection play an im-portant part in the thickness and density of thepericyst, as well as on the reproductive activitiesand survival of the cyst itself. An uninfected cystof even 40 to 50 years' growth may have a pericystof only f- to i in. in thickness because the host'stissues have not received the stimulus necessary toproduce much fibrous tissue. If, however, low-grade infection occurs, the threat of death to theparent cyst causes intense reproductive activityand it becomes packed with daughter cysts andbrood capsules. The host's tissues at the sametime react and a thick-walled pericyst up to in.of dense fibrous tissue may result.

Alveolar Hydatid Disease of the LiverThere is an unusual form of hydatid infection

known as alveolar hydatid disease, or echino-coccosis alveolaris. I operated in February, 1940,on the only case to be reported from New Zealand,and full details of the pathological condition werereported by Meade and Barnett (I94x).A woman, aged 59, was admitted to the medical

wards in 1928 complaining of epigastric pain oftwo weeks' duration. The liver was then found tobe smooth and grossly enlarged. The hydatidcomplement fixation test was negative. She wastreated for hypertension and myocardial failurewhich were also present. She was fairly well until

I940, when she was admitted under my care com-plaining of loss of weight and of a tumour in theleft upper part of the abdomen. On examinationthe abdomen presented a firm swelling in theepigastrium projecting down to below' the um-bilicus. The hydatid complement fixation andCasoni tests were negative. Radiological examina-tion revealed elevation and decreased movement ofthe left half of the diaphragm with some irregu-larity in outline of the right half. The stomachwas displaced by extrinsic pressure.

In view of the long history and uncertainty ofdiagnosis a laparotomy was performed. A cyst4 in. in diameter bulged from the left lobe of theliver. It contained typical gelatinous debris of anold and degenerated hydatid cyst. Occupying theright lobe of the liver was a hard, finely nodularmass, yellowish grey in colour and looking verylike secondary carcinoma. A biopsy was takenand was sent to the laboratory as a suspectedcase of alveolar hydatid. The biopsy specimenpresented numerous small cyst-like spaces sur-rounded by fibrous tissue, foreign body giant cellsand inflammatory-celled infiltration. The patientbecame hemiplegic eight days after operation anddied in coma on the tenth day. Post mortemfindings are fully recorded in the paper by Meadeand Barnett (194I).

This type of lesion is endemic in SouthernGermany, Switzerland, the Tyrol and theCaucasus, and its absence in other parts of theworld where hydatid disease is common, led tothe belief that there were two different species ofechinococcosis. In more recent years sporadiccases have been reported over a wide area andopinion has swung back to the acceptance of butone species of hydatid, the alveolar form being amutation. Just as the terrain influences thegrowth in bone, so under certain as yet unknownconditions the liver may act in a somewhat similarway. The alveolar hydatid grows by extrusion andexogenous budding of the germinal layer, thehydatid ectocyst being poorly developed.

Surgical Treatment of Hydatid Cysts ofthe LiverThe majority of cases coming to operation have

laboratory and radiological findings which makethe diagnosis of hydatid highly probable. Thereare, however, a number found unexpectedly dur-ing the course of abdominal operations for lesionselsewhere, and not uncommonly for supposedcholecystitis or gall stone disease.

Surgical approach should be planned to give themost direct access if one is certain that only onecyst is present, or if the condition of the patientprecludes the immediate treatment of cysts else-where. The danger, inherent in a limited exposure,

March 1949

POST GRADUATE MEDICAL JOURNAL

of failing to ascertain the presence of other cystsis obvious. Another serious risk is taken, if theexposure is not adequate, of ' hydatid spill,' anaccident that may lead to life-long recurrences.I know of no condition requiring greater careto avoid soiling of wound edges and peritoneumthan that demanded by a hydatid cyst about to beopened. ' Hydatid asepsis' is essential. A cystuncomplicated by adhesions, carefully packed offfrom the wound edge and the peritoneal cavity,on being relieved of some of its fluid content,immediately slides away from the abdominal orchest wall, and what appeared to be a carefullysafeguarded area may easily become a dangerpoint for spread of scolices.

It has become an accepted principle to use 2 percent. formaldehyde solution in an attempt to killscolices prior to opening the cyst. After thewound and peritoneal surfaces have been packedoff, the cyst is tapped by a trocar attached to a tubeand funnel, and some hydatid fluid is allowed torun out. This is replaced by formalin solution.Gradually the hydatid fluid is replaced by formalinand at least five minutes are given to allow it toact. Up to this stage there should have been no spill.

Tension sutures are now applied on either sideof the proposed incision and when they are inposition the formalized fluid within the cyst isaspirated, while simultaneously the tension suturesare pulled on to prevent spill and assure that thewound and peritoneal cavity remain shut off. Thecyst may now be incised.When the cyst tension has been reduced the

mother cyst falls away from the pericyst and canbe gently removed, often intact, with spongeforceps. If many daughter cysts are present, afteran initial gush, a prolonged and careful removalwith spoon or large ovum forceps is necessary.The interior of the cavity is then swabbed overwith 2 per cent. formalin. In old degenerate cystspart of the parent membrane adheres to the peri-cyst.

If the mother cyst is tightly packed withdaughter cysts the initial formalization fails toreach the scolices and the risk of dissemination iscorrespondingly greater. There is need for amore efficient and less dangerous antiseptic thanformalin solution.

If the surgeon finds the liver adherent to theabdominal wall over the cyst, and he can availhimself of this area, there is no risk of spill, butof course he cannot explore elsewhere. Adhesionsare likely to be found in old cysts with superaddedsepsis.

There can be no hard and fast rules regardingthe surgery of access, and no more than generalprinciples and personal inclinations can be givenhere.

Definite indications for exploration through theabdominal wall are (i) All cysts that can be reachedby this approach; (2) The presence of obstructivesymptoms in the biliary tract; (3) Evidence ofhydatids elsewhere in the abdominal cavity.

Definite indication for a posterior trans-thoracic approach are when intrathoracic com-plications such as empyema, lung abscess orbroncho-biliary fistula complicate a liver cyst thathas burst through the diaphragm.

In certain cases of ' dome cysts' presentingposteriorly there is debate as to the advisability ofa thoracic approach, either after elevating thepleural reflection and excluding it by suture of thediaphragm to the chest wall, or of doing a two-stage operation. The added risk of pleural infes-tation, and the fact that practically all recognizablecysts can be reached from an anterior trans-peritoneal approach deter many from adoptingthe thoracic route.

For the abdominal approach a Kocher's in-cision, extended as necessary, gives good access toboth lobes of the liver and the biliary passages.The high-lying cyst under the right cupola, iflarge, will usually extend down sufficiently to beaccessible through liver tissue below the costalmargin. The costal margin may be resected, andthe pleural reflection stripped up, to give as wide anaccess as required. When the tension of a largecyst is eliminated it may be possible to palpatefurther cysts.The treatment of the cavity lined by pericyst

left after removal of the cyst raises many problems.If there is bile leakage or evidence of biliaryobstruction (in which case the common bile ductshould also be explored for daughter cysts) orsuppuration, the cavity must be drained. Thepericyst is sutured to the opening in the abdominalwall (marsupialization) and convalescence will beslow.

If the daughter cysts are stained yellow fromprevious bile leakage and the parent membrane isdegenerate, it is highly probable that drainage willbe required. If the cyst is healthy and uncom-plicated it may be filled with saline, and the peri-cyst'closed. It is a wise precaution to suture thepericyst to the abdominal wall and leave theabdominal wall in a condition that will permitsinus forceps to pass into the cyst without dangerof spread of infection or leakage of bile. Penicillinand sulphanilamide will probably make primaryclosure safer than in the past, but owing to bileleakage and mild infections the results of primaryclosure have not been invariably satisfactory incases generally recognized as being suitable forthis form of treatment. Bile leakage into thecavity may be delayed for several days. A com-promise may be effected in doubtful cases by

March I949II4

March 1949 JENKINS : Hydatid Disease .115

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FIG. I.-Case A. Showing recurrent hydatid cyst inthe right lobe of the liver occurring in a child ofthree. The original cyst was operated on at threeyears ; the recurrence shown, of similar size, at sixyears of age. Note the bulging of the ribs on theright side.

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FIG. 2.-Case B. Radiogram of the chest of a childeight years of age illustrating the size to which alung cyst may grow in the early years of life.

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FIG. 3.-Case E. A bronchogram showing pressureeffects of the cyst on the right lower lobe of the lung.

FIG. 4.-Case E. Showing a cyst at the base of theright lung.

xi6 POST GRADUATE MEDICAL JOURNAL March I949

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FIG. 5.-Showing a calcified pericyst in each of twohydatid cysts discovered during an X-ray examina-tion of the urinary tract. Patient aged eight years.

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FIG. 6.-Case F. Sho\xing a barium meal vitll gro;sdistortion of the fundus of the stomach by ahydatid cyst under the left diaphragm. The out-line of the cyst is clearly seen.

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FIG. 7.-Case G. Showing elevation of the diaphragmresulting from a large cyst in the right lobe of theliver.

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F:c. 8.-Case H. Showing in the left lung severalcysts approximately - in. in diameter. In the rightlung there are multiple cysts of varying size.

March I949 JENKINS: Iydaltid Disease I17

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FIG. 9.-Case I. Showing a hydatid cyst in the rightlung.

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Fic. Io.-Case J. Showing a circular shadow of .in-creased translucency in the loN;er part of the rightlung x-ith what is probabl collapsed hydatid menm-brane in the lower part of the cyst.

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lI;G. ii.-Case K. Showing a large cyst with thehydatid membrane presenting the characteristicwavy mass (' Sign of the Camelote ').

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FIG. 12.-Case L. Myelogram showing blockage atlevel of T. 12. Medium injected into cistcrnamagna. Note erosion of ribs and vertebrae,

isIOST GRADUATE MEDICAL JOURNAL March 1940

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Fic,. 13.-Case M. Showing hvdatid invasion of ribs.

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Fic.. I4.-Case N. Lipiodol myclogram showing de-formitv of lower end of thecal column by extraduraltumour on right side at lumbosacra! leve!.

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Fi(,. 15.-Case 0. A retrog;rade pvelogram with ap-pearances suggestive of a hypernephroma. Theureter is displaced. The pelvis of the kidney isobliterated and there is elongation and deformity ofthe upper and lower major calices.

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FIG. I6.-Case P. A retrograde pyelogram showing alarge tumour mass which caused rotation of thekidney, some hydronephrotic changes and dis-placement of the ureter.

JENKINS: Hydatid Disease

closing the pericyst and leaving a drain down to it,but here again the hazard of infection occurs.

In view of the great rapidity with which thehuge cavity shrinks, the frequency with which bileleaks into it and, finally, the need for drainage in aconsiderable percentage of closed cases, the ' nodrain' method stands on trial at the presenttime. One final warning should be given re-garding the handling of the pericyst. There mustbe no trauma with finger, spoon or other instru-ment to the wall of the cavity as large vessels andducts may be eroded, and but a fragile membranemay separate the cavity from the duct lumen.

HYDATIDS OF THE LUNGSHydatid cysts in the lung may arise in several

ways :-(a) The hexacanth embryo may pass thefilter of the portal circulation and so reach thelungs. This probably accounts for solitary lungcysts (Fig. 2). (b) Leakage of a liver cyst or cystelsewhere into the venous system may lead tomultiple lung cysts, which will usually be ofapproximately the same size (see the left chest,Fig. 8). (c) Liver cysts may erode the diaphragmand secondarily involve the lungs.Lungs presenting numerous cysts of varying

ages and sizes are difficult to explain. Inter-mittent rupture of pulmonary cysts into thebronchial tree with subsequent implantation ofscolices throughout the lungs is a possibility.Intrapulmonary vascular spread is also a possibleexplanation.

Case H.-Illustrating multiple lung cysts ofvarious sizes.A woman, aged 53 years, was admitted in July,

1945, giving a history of pain in the chest and ofspitting of blood for I6 months in amountsvarying from i oz. to 5 oz., at approximatelymonthly intervals. She gave a history of pneu-monia two years previously and of pleurisy fourmonths prior to admission. A diagnosis ofcholecystitis had also been made recently elsewhere.On examination there were marked physical

signs in both lungs. The Casoni test was weaklypositive (immediate). The delayed reaction wasnegative. The hydatid complement fixation testwas strongly positive. Eosinophilia, 7 per cent.An X-ray of the chest disclosed multiple cysts inboth lungs, four in the left lung of approximatelyequal size, and innumerable cysts in the rightlung of varying size (Fig. 8).

Operation. On 10.7.45, 7 in. of the eighth, ninthand tenth ribs were resected on the right side andmultiple cysts of the pleura were removed. Thesecysts were mostly less than i in. in diameter, andlay in a thickened adherent pleural covering.(They were probably due to the intrapleural rup-

ture of a lunig cyst.) One large cyst was evacuated.There was a bronchial fistula into the pericyst. Acyst was palpated through the diaphragm and thiswas also evacuated. The wound was looselypacked with sulphanilamide and flavine gauze.On 4.9.45 the cysts in the upper part of the right

lung were dealt with; 3 in. of the third, fourthand fifth rib were removed posteriorly. Manypleural cysts were encountered and one lung cyst.The wound was packed as before.On 24.9.45 the large cyst near the mediastinum

and several smaller cysts were removed. Thewound was packed as before. The patient wasdischarged on 19.10.45 with all wounds healed.

Comment. Palliation alone is possible in casesof this nature. The probable sequence of eventshad been the rupture of a lung or liver cyst intothe pleural cavity with resulting obliteration, theseeded secondary hydatid cysts being enclosed inthe thickened pleural membrane. At a later stagea larger lung cyst communicated with a bronchus.A possible explanation for the cysts in the leftlung is given above.Another interesting feature in this case was the

finding of fibro-caseous tuberculosis in some lungtissue removed with the pleural cyst.The ' life' of a lung cyst depends mainly on its

avoidance of pressure on a bronchus, obstructiveeffect on pulmonary tissue, or secondary in-flammatory change. Cysts in children usuallygrow to about 3 in. in diameter before complica-tions occur and in adults they are correspondinglylarger. When a cyst erodes a bronchus thehydatid membrane may remain intact, but sooneror later rupture is liable to occur. This is charac-terized by flooding of the bronchial tree with thetypical watery fluid content of the cyst. Daughtercysts are relatively uncommon. The hydatidmembrane may be expelled and spontaneous curetake place, but usually they separate from the peri-cyst and remain as a loose mass within the cavity.Secondary infection is only too probable, resultingin chronic lung abscess. Insidious leakage of thewatery cyst content is of commoner occurrencethan a sudden acute rupture, and this may lead topartial separation of the membranes from the peri-cyst and the ' single arc sign,' or the 'sign of thecamelote' may be seen radiologically (Jenkins I946).

Rupture into the pleural cavity is uncommon.Injudicious use of an exploring needle may readilyprecipitate this disaster. Hydatid pneumothorax,haemothorax and pressure pneumothora, mayoccur, and at a late date secondary echinococcosismay develop in the pleura, lung or ribs (.pse H).

Pneumonitis and pleuritic pain are pommonresults of pressure and infection. As bje cystapproaches the visceral pleura pressure may mndcepleural adhesions.

March I949 ' II9

POST GRADUATE MEDICAL JOURNAL

The pericyst varies enormously in lung cysts andon its state largely depends whether a simpledrainage operation or a lobectomy should be per-formed. In uninfected peripheral cysts, thepericyst is usually thin and pliable, and when thecyst is opened and the membrane removed, thereis nothing to prevent the lung from re-expandingfreely and occupying the space previously occupiedby the cyst.

Case I.-Illustrating a solitary cyst of the lung,' single arc sign-' probably present.A boy aged 71 had suffered pain in the right

side of his chest for 24 months before admission.Cough had been troublesome and he had been outof sorts and had run intermittent temperatures upto Io3°F. A radiograph (Fig. 9) showed a shadowsuspicious of a hydatid cyst. It was thought thatCumbros sign or the ' single arc sign ' was present.Both the hydatid complement fixation test and theCasoni tests were strongly positive. On physicalexamination the breath sounds were loud, withprolonged expiration in the right axilla at thelevel of the sixth rib.

Operation, 1.9.45. Local anaesthetic, i percent. procaine; 2i in. of the fourth and fifthribs were removed. The pleura was adherentover a small area, and the pericyst was enteredwithout involving the pleural cavity. The mem-branes were removed. There were no daughtercysts. The cavity was wiped out with formalin,there being no bronchial communication. Thecavity was drained for a few days. The child wasdischarged healed and well i8 days after operation.

Comment. If the pleura had not been foundadherent, and this can be ascertained withoutopening the parietal pleura, a two-stage operationwould have been performed. The absence of awell-formed peiicyst permitted the expandinglung tissue to obliterate rapidly the cavity leftafter the removal of the cyst. In cases such asthese there can be no indication for lobectomy withits added risk. Even in the presence of multiplebronchial fistulae into the pericyst, rapid healingwill occur if there is no rigid-walled pericyst tomaintain the patency of the cavity.

Case J.-Illustrating an infected cyst communi-cating with a bronchus.A woman aged 49 was seen on 4.3.47 giving a

history that three weeks previously she hadcoughed up about 2 pt. of watery fluid followedby blood. Her doctor suspected a hydatid cyst.The radiograph (Fig. io) showed a circular shadowof increased translucency in the lower part of theright lung partly hidden by the dome of thediaphragm. What is probably collapsed hydatidmembrane is seen at the lower part of the cyst.

Both the hydatid complement fixation test and theCasoni test were strongly positive. Physicalexamination revealed dullness at the right basewith diminished breath sounds. A coarse, short,rasping sound was heard during the inspiratoryphase.

Operation, 17.3.47. Intratracheal anaesthesia;7 in. of the eighth rib were excised and ~ in. re-moved from the posterior end of the seventh rib.The pleura was densely adherent and the lungtissue felt semi-solid. The cyst could not be de-fined owing to its collapsed state and the changein the surrounding lung tissue. On account of thepatient's general condition lobectomy was decidedagainst. The pericyst was cut into and collapsedmembrane representing a cyst of 6-7 in. indiameter was removed. No daughter cysts werepresent. There was much muco-pus present andthe openings of several large bronchi could be seen.The cavity was lightly packed with flavine sul-phanilamide gauze and a drain inserted. She wasdischarged from hospital 27 days after operationwith a large sinus having visible fistulous openingsof bronchi at its inner end. These openings werecauterized with silver nitrate at intervals duringthe next month and the wound was completelyhealed and the patient symptom free by 6.6.47.

If there has been long-standing fistulous com-munication between the hydatid cyst and abronchus associated with infection, there will be afixed sclerosed unyielding pericyst, and it may begreatly in the patient's interest to perform lobec-tomy if it can be safely carried out. Damage tothe bronchial tree shown by a bronchogram maybe an added indication for this procedure.

Case K (Fig. ii).-Illustrating a large infectedcyst in a child in whom lobectomy was carried out.A female, aged 6 years, was referred in October,

1944. She was said to have had a left sidedpneumonia four months previously. At intervalssince then she had developed temperatures. Therewas no cough or sputum, and there was no historyof coughing up any clear fluid. Radiologicalexamination showed a large cyst with the hydatidmembrane showing the characteristic wavy mass(' sign of the camelote '). On November 3rd,under local anaesthesia and intratracheal gas andoxygen, the chest was opened. The cyst wall(pericyst) was very thick and rigid. The pressureswithin the cyst showed, by tapping it with a fineneedle, that it communicated with a bronchus.Further examination revealed that the cyst layentirely within an expanded middle lobe. Themiddle lobe and the enclosed cyst were removed,the bronchus being closed with interrupted cottonsutures. Convalescence was without incident andthe patient was discharged healed on the 20th day

120 March 949

JENKINS: Hydatid Disease

Comment. If drainage had been carried out inthis case it would have been prolonged and itis probable that a residual cavity communicatingwith the bronchus would have persisted through-out life. Chronic bronchiectasis would have beenlikelyThe Surgical Treatment of Lung CystsAs with a lung abscess, so with hydatid, both are

' infected' in their own way. No needle shouldever be put through a chest wall for diagnosticaspiration of a suspected lung cyst. The resultingdisaster may be as great as with lung abscess.

In simple uncomplicated cysts careful localiza-tion should be carried out, and segments of tworibs resected over the point at which the cyst isnearest to the chest wall. When the extra-pleuralplane is freely exposed one can see whether or notthe lung is adherent. If the parietal pleura isthickened and there is no sign of movement of theunderlying lung, entry can be made directly intothe lung at this point. The area of adhesion maybe limited to an inch or less.

If adhesions are not present it adds but tendays (to the many years the hydatid has beenpresent) to induce their formation by an extra-pleural iodine gauze pack. A high percentage ofthese cases has to be drained on account ofbronchial fistula or sepsis. One does not knowbefore operation what the interior of the pericystwill present as the tense membranes may beoccluding an opening into one or more bronchi;openings that become only too apparent once themembranes are removed. The risk of the cavityin the lung, with its associated bronchial fistula,producing pressure pneumothorax due to faultysuturing or to stitches cutting out, is too high topermit of pleural suture and immediate evacuation.

If forced to do a one-stage operation in theabsence of pleural adhesions, a water seal drainageof the pleural cavity should be carried out. Theuse of formalin in lung cysts is to be stronglycondemned except for swabbing the pericyst inthe absence of bronchial fistula. Some textbooksadvocate injecting formalin into the cyst beforeopening it, as is done in the case of liver cysts,but this procedure carries many dangers as theformalin may enter the bronchial tree if a fistulais present.

Small cysts lying deeply in the lungs are bestleft alone. The size and progress of the cystshould be watched by radiograms at yearly inter-vals. Where there are multiple cysts the sameprinciples of treatment apply as in the single cyst,but it is often possible to drain two or more cyststhrough one approach. The prognosis in lungcysts is good, both as regards absence of recurrenceand subsequent lung function, providing ' no spill

technique' and a careful choice of procedure isadopted. The case becomes almost hopeless onceintrapleural dissemination with involvement ofribs and intercostal structures occurs.

HYDATIDS INVOLVING THEVERTEBRAL COLUMN

I have encountered three of these cases and theyconform to type to an extraordinary degree. Intwo cases there has been a life-long history ofpulmonary hydatid, both patients being pastmiddle age. Repeated operations have been per-formed elsewhere for pulmonary cysts, extra-pleural tissues involved, and the body of one or'more vertebrae invaded. The course of the diseasehas been insidious and progressive. One canassume that at the original operation, had spillbeen avoided, the story might have been a verydifferent one.The extraordinary changes in the response of

the hydatid to its environment are strikinglyexemplified by these cases. In the lungs there isformation of large cysts of the usual type; in thearea adjacent to the spine, intervertebral foraminaand spinal canal are cysts mostly i to 1 in. indiameter, free and without pericyst, while in thecancellous bone' of the vertebrae are cysts of aminute sago-grain structure causing diffusedestruction. Another feature is the apparentability of the cysts to derive essential nourishmentfrom the body fluid when they are lying free intissue spaces and not surrounded by a pericyst. Ineach of these cases cysts had worked through theintervertebral foramina and caused extraduralpressure and paraplegic symptoms. The tendencyfor the cysts in spreading to take the line of leastresistance, via the intervertebral foramen is verystriking. In each case at laminectomy an extra-dural cyst was found. When the intervertebralforamen was investigated and further bone re-moved, cysts were found in an extrapleuralposition.

Case L.-Illustrating hydatid of lung andvertebrae.A female, aged 45 years, was seen in consulta-

tion with Mr. Murray Falconer, to whom I amindebted for permission to use this record. Thepatient was admitted to the Neurosurgical De-partment with symptoms of cord pressure.

In 1920, at the age of 21, she suffered frompleurisy. At the age of 25 she was admitted to asanatorium for chest complaints and remainedthere for four years. The condition which hadbeen suspected as being tuberculosis was thenfound to be hydatid. She had an operation forlung hydatids in 1928. In 1929 she coughed up acyst and this was followed by multiple haemor-

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POST GRADUATE MEDICAL JOURNAL

rhages and further coughing up of cysts. In I936she had a further lung operation followed bycoughing up of more cysts, pus and blood. In1943 and I944 she had abdominal operations forhydatid cysts.

Neurological examination confirmed pressure onthe cord at the level of the i2th thoracic vertebra(Fig. 12). X-ray examination showed destructionof the inner end of the Iith and I2th ribs, and thetransverse processes and pedicles of the i ith and12th thoracic vertebrae. Changes are seen in theix th and 72th thoracic vertebral bodies on theright sideAt operation a large cyst was found in the lower

part of the right lung. This was adherent to theside of the vertebral column and had eroded it.Numerous daughter cysts were present and thedisease extended through the intervertebral fora-mina to involve the extradural space. A right,hemilaminectomyv and costotransversectomy re-vealed a mass of daughter cysts up to i cm. indiameter along the right lateral border of thetheca. Removal of the i2th rib and right trans-verse process freed a large collection of cysts belowthe diaphragm with further cysts in the liver. Thediaphragm appeared to be intact. On discharge24 months later the cord pressure was relieved andthe wound was healed.

She was readmitted in December, 1945, com-plaining of low back pain. There was no evidenceof spinal cord pressure. Multiple cysts were re-moved from the base of the right lung.The next admission was in September, 1947.

She was suffering severe pain, and had difficultywith micturition. There had been further opera-tions for cysts and an Albee operation performedelsewhere. Operation was undertaken on 19.9.47by Myf James of the Neurosurgery Departmentand myself. The dura was found to be absent atthe level of the I2th thoracic vertebra on the rightside and several cysts extended intrathecally.There was marked pressure on the cord. Thebody of the I2th thoracic vertebra was a mass ofsago grain-like material; it was vascular, softand spongy and contained millions of pin-headcysts. The whole of this was curetted awayleaving part of the shell of the vertebral body.The adjacent discs were removed. The erectorspinae muscle was split and the inner part used torepair the dural defect and to fall into the bonecavity. On 7.11.47 a massive bone graft wasapplied bridging the gap left by the loss of thebody of the i2th thoracic vertebra. Healing wassatisfactory. Up to the present time there hasbeen no further evidence of pressure on the cord.

Case M.- Illustrating hydatid disease of lungand vertebrae.

A male, aged 52 years, was first seen inNovember ix9i complaining of pain in the dorsalregion with evidence of spinal cord pressure, bothbeing present for three months prior to admission.Forty years previously, at the age of I2, he had hada hydatid of the left lung removed. At the age of19 he coughed up hydatid cysts. Three years laterhe coughed up more cysts. Some years later acyst burst through the front of his left chest.Twelve years ago he had cysts removed from theback of his neck. Five years ago he was operatedon for further cysts in the lungs.On examination he showed signs of pressure on

the cord at the fifth dorsal segment. The Casoniand hydatid complement fixation tests were bothstrongly positive. An X-ray showed much pleuralthickening with cysts lying in the posterior partof the left lower lobe, their medial borders in close-relationship to the vertebral bodies. No bonylesion was detected.At operation a laminectomy was performed and a

cyst was found in the extradural space causingpressure on the cord. It had an hour-glass shape,extending through an intervertebral foramen, partof the cyst being within the spinal canal and partwithin the thorax. Removal of transverse pro-cesses revealed a cavity containing further smallcysts. This space was extrapleural and the bodyof the sixth dorsal vertebra and its transverse pro-cess were eroded. The spinal theca was notopened during the operation. The patient madea satisfactory recovery and lost all symptoms ofcord pressure.He next reported in February, I944, again with

pain in the dorsal spine and gross pulmonary dis-turbance. He was very toxic and was coughing upcopious offensive sputum. X-rays showed furthercysts in the left lung. Under local anaesthesia andpentothal an attempt was made to provide drain-age. The ribs were diffusely involved with hyda-tids, as were the soft tissues of the chest wall.The vertebral bodies were eroded and there werethree cysts in the lung. All these structures wereadherent and the spread of the disease wasapparently by a continuous process of infiltrationby the disease (Fig. I3, showing erosion anddestruction of ribs).

Case N.-Illustrating hydatid disease of thesacro-iliac region.A female, aged 20, was admitted under Mr. M.

Falconer on 7.10.43 with a provisional diagnosisof sciatica due to a prolapsed intervertebral disc.She had suffered low back pain and sciatica forI8 months. This had been very severe at times.She had recently experienced difficulty in empty-ing her bladder. On examination there weremuscular wasting and sensorv changes in the right

March 1949122

JENKINS: Hydatid Disease

leg, and neurological investigation suggested anextradural tumour at the fifth lumbar - first sacrallevel. A prolapsed nucleus pulposus was con-sidered likely, though an extradural tumour wassuggested by the large size of the filling defect(Fig- 14).At operation Mr. Falconer found an extradural

hydatid cyst arising from the body of the secondsacral vertebra. It wag roughly 5 cm. in diameter,and had eroded completely through the sacrum ex-posing the pelvic fascia on its deep surface. Therewas no visible pericyst. After operation the hydatidcomplement fixation test was strongly positive.She was readmitted in December, 1945, when

Mr. Falconer asked me to see her in consultation.She then had a firm, tender swelling in the rightsacro-iliac region. She was running a temperatureup to 100.5° F. Her hydatid complement fixation.was strongly positive and the Casoni test was in-determinate. X-rays of the bony pelvis and lum-bar spine showed no appreciable bony abnormality.There were no fresh neurological signs or symp-toms. At operation we found the sacrum andadjacent ilium riddled with hydatid cysts varyingin size from a pin head to i cm. diameter.

Comment. This third case of vertebral in-volvement appears to be a primary bone infectionin that no lesion has been found elsewhere. Theprognosis is very bad. The widespread infiltrationof the sacrum and ilium makes complete removalimpossible. With infiltration of cancellous boneradiological changes aie in its early stages eitherabsent or of such slight degree that the conditionis likely to be missed.

PRIMARY CYSTS IN OTHER PARTSOF THE BODY

If the hexacanth embryo passes through thefilter of the liver and the lung it is easily under-standable that a primary cyst may occur in any partof the body. 'The kidney is involved in about 2 percent. of c?sec

In the kidney the cyst may grow to large pro-portions, but rupture or leakage into the urinarytract is likely to occur sooner or later. Daughtercysts may pass down the ureter causing uretericcolic. Infection is common, leading to markedthickening of the pericyst, which may be fusedwith the expanded kidney capsule and surroundingstructures.

Case 0 (Fig. 15).-Hydatid simulating a renalneoplasm.A female, aged 6i years, complained of pain in

the right loin, and showed a large tumour mass inthe left flank.

Investigation elsewhere had led to a diagnosisof hypernephroma. Examination revealed a very

sick, hypertensive woman. A large rounded massfilled the left upper 'abdomen. The tumourpresented in front like an enlarged spleen but nonotch was felt. It did not fill the loin. An intra-venous pyelogram showed a normal right kidneybut only part of the pelvis on the left side, nocalices being seen. Cystoscopy confirmed very poorfunction on the left side and a catheter could notbe passed beyond I5 cm. Bladder urine containedpus, though the urine from the right kidney wasclear. Retrograde pyelograms (Fig. i5) gave anappearance not unlike that of a hypernephroma.The large rounded mass of the tumour was seento cause displacement of the ureter and obliterationof the pelvis with elongation and deformity of theupper and lower major calices. At operation by a-left loin incision a large, thick walled cyst wasremoved. The kidney was incorporated in its walland the spleen was so densely adherent that boththese structures were removed with it. Con-valescence was satisfactory. The cyst was foundto be full of pus, daughter cysts and hydatiddebris. The kidney was an infected, fibrosed,functionless structure stretched over and fornlingpart of the cyst wall.

Comment. Two procedures were possible inthis case. The easier and probably safer was toopen and drain the cyst. The patient would havehad a very prolonged convalescence owing to thethickness, rigidity and infection of the pericyst.Radical removal was carried out in this case owingpartly to the fact that at the commencement Ithought I was dealing with a renal tumour, andlater when the true position was disclosed it wasdeemed possible to complete its removal. Simple,non-communicating, uninfected cysts may betreated according to principles followed in thetreatment of cysts elsewhere. In certain cases apartial nephrectomty may be possible.

Case P (Fig. I6).A female, aged 65 years, was admitted to the

medical ward with epistaxis. She was markedlyhypertensive, systolic blood pressure 262, diastolic70. In the course of examination a tumour wasfound in the right flank. The tumour wasrounded, tense and cystic. On its lower anteriorsurface it was irregular and firm. Intravenouspyelograms showed no function in the rightkidney. A retrograde pyelogram (Fig. i6) revealeda large tumour mass causing rotation of the kidney,slight hydronephrotic changes and displacementof the ureter. Urea concentration tests showed2.54 per cent. in the fourth specimen. The Casonitest was negative. At operation a large hydatidcyst was found tightly packed with daughter cysts.This was emptied, formalized and drained. Con-valescence was uneventful. The firm, irregular

March 1 949 123

124 POST GRADUATE MEDICAL JOURNAL March r949

area was a 2 in., smaller degenerate cyst attachedto the large cyst.SummaryOnly certain aspects of the wide field of hydatid

infection have been touched upon in this paper. Inmany cases the surgical problems are compara-tively simple, but not in all, and I have attemptedto present the disease as I have seen it. It will beapparent that there can never be a 'best singlemethod ' for there is a greater demand for adapta-bility and versatility in the treatment of this disease

than for any other surgical condition. Finally thethought must ever be in the operator's mind that'spill' may mean life-long suffering for thepatient.

BIBLIOGRAPHY

BARNETT, L. E. (1927), M. J. Atst., 2, 878.HUTCHINSON, JONATHAN (1890), Arch. Surg., I, 3X8.JENKINS, JAMES A. (I93x), Brit. J. Surg., I8, 585.JENKINS, JAMES A. (I946), Aust. and N.Z. J. Surg., IS, 296.MEAD, A., and BARNETT, L. (1941), Aust. and N.Z. J. Surg.,

10, 3I7.SYME, G. A. (I909), Brit. Med. J., 2, 956.

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