Pancreatic cystic lesion by xiu

MR Imaging ofMR Imaging of Cystic Lesion of the PancreasCystic Lesion of the Pancreas

Present by : Ekksit Srithammasit, MDPresent by : Ekksit Srithammasit, MD

Kalb et al : Departments of Radiology , Surgery, and Pathology, Emory University School of Medicine, Atlanta.

2009;

IntroductionIntroduction

Pancreatic cystPancreatic cyst A common incidental finding in

cross-sectional imaging. Neoplastic VS Nonneoplastic

processes. Require surgical intervention VS

follow-up.

IntroductionIntroduction

The role of pancreatic cyst biopsy is debated.

Biopsy of a malignant fluid-containing lesion may lead to spread of malignant cells.

Histological analysis and chemical analysis produce a questionable diagnostic yield.

IntroductionIntroductionImaging detailed of pancreatic cyst : Cyst morphology Fluid content Communication with the pancreatic ductal

system. Entire pancreatic parenchyma

MRI = best suited for evaluating these features.MRI = best suited for evaluating these features.

Imaging ModalitiesImaging ModalitiesUltrasound

Lack of spatial resolution. Lack of soft-tissue

contrast resolution. Limited in large patients. Endoscopic US is

invasive.

Presence or absence of calcification : Presence or absence of calcification : notnot critical critical factor in the differentiation of pancreatic cyst.factor in the differentiation of pancreatic cyst.

CT Can depict small

pancreatic cysts. Limited to evaluated

internal septa of the cyst. Better demonstrated

Calcification.

Imaging ModalitiesImaging Modalities

MRI Good soft-tissue contrast. Clearer depiction of septa and other

cyst contents. Good to depiction of pancreatic ductal

system.

MRI = best suited for evaluating these features.MRI = best suited for evaluating these features.

Table of ContentsTable of Contents MRI Technique Overview of lesions

PseudocystSerous CysadenomasMucin Containing CystLymphoepithelial CystSolid Pancreatic Tumor with Cystic

Degeneration

MR Imaging TechniquesMR Imaging Techniques

T2W sequences.Fat saturation.MR cholangiopancreatography.

Dynamic 3D contrast enhanced T1W GRE sequences.


T2WI : coronal and axial planesT2WI : coronal and axial planes Cyst contents (fluid, septa) Pancreatic duct system.

Fat saturation. Allows the identification of acute

inflammatory changes. Improve depiction of the internal

architecture of a cyst.


MR cholangiopancreatography MR cholangiopancreatography (heavilyT2-weighted sequences)(heavilyT2-weighted sequences)Depiction of the ductal system Small communications between cystic

lesions and the pancreatic duct.

MR Imaging TechniquesMR Imaging TechniquesUnenhanced and contrastUnenhanced and contrast--enhanced T1-enhanced T1-

weighted imagesweighted images..

Enhancing soft-tissue components. The surrounding pancreatic parenchyma The pancreatic duct. Unenhanced T1WI:

Internal hemorrhage.Protein deposits.



Degeneration

PseudocystsPseudocysts

M/C cystic lesions of the pancreas.

Occur in the setting of pancreatitis: Hemorrhagic fat necrosis and encapsulation

by granulation tissue and a fibrous capsule.


Irregularly marginated -> Well circumscribed, with a thickened.

Blood products and necrotic or proteinaceous debris. Intrinsically increased T1 signal intensity.

Acute or chronic pancreatitis.

PseudocystsPseudocysts Inflammation:

Increased SI surrounding a complicated pseudocyst on T2FS. Cause of inflammation is more likely to be chemical irritation than

infection Impossible to differentiate between an infectious process and

other possible causes on the basis of imaging features alone.

Dissect along abdominopelvic fascial planes to sites remote from the pancreas eg, liver, pleura, or mediastinum

Fistulation may occur between a pseudocyst and one or more vascular structures.

PseudocystsPseudocystsNo vascularized soft-tissue elements are present within

pseudocysts, and if vascularized elements are seen within a cystic lesion on contrast-enhanced MR

images, the lesion is not a pseudocyst.


DDx with Mucinous cystadenomaDDx with Mucinous cystadenoma Mucinous cystadenomas often persist

without a significant interval change on F/U images.

Evidence of acute or chronic pancreatitis almost always found in pancreatic pseudocyst, not in mucinous cystadenoma.

Pancreatic pseudocyst.

(a) a simple fluid collection. (b) with chronic pancreatitis.

Pancreatic pseudocyst with F/U 2 months

(a) Complex cyst with a fluid-debris level (b) Resolution of the pseudocyst.

Pancreatic pseudocyst

Common findings in pancreatic pseudocysts: hemorrhage, protein deposition.



Degeneration

Serous CystadenomasSerous Cystadenomas

Benign cystic neoplasms Occur frequently in older women (median age,

65 years). Usually discovered incidentally. Large cyst may cause abdominal pain or,

more rarely, jaundice. Multiple serous cystadenomas may occur in

von Hippel–Lindau disease.

Serous CystadenomasSerous Cystadenomas Composed of numerous

small cysts: honeycomb like formation.

Size typically less than 1 cm ( 0.1-2 cm ).

Lined by glycogen-rich epithelium.

Fibrous septa that radiate from a central scar.

Central scar may be calcified.


MR imaging: MR imaging: Classic type - microcystic formClassic type - microcystic form A cluster of small cysts of simple fluid SI. No visible communication between the cysts and the

pancreatic duct. Delayed enhance of thin fibrous septa between small

cysts. Central scar : with or without coarse calcification. Progressive enlargement ≥ 4 cm may be seen at

serial follow-up over a period of months.


MR imaging: MR imaging: Less common types:Less common types:

Oligocystic variant: Oligocystic variant: Cysts are larger and

fewer. May mimic that of a

mucinous cystadenoma.

Solid variant: Solid variant: Composed of microscopic

serous cysts that too small to be reliably depicted on MR images.

MRI: solid, well-circumscribed, well-vascularized mass.

Features that overlap with those of pancreatic neuroendocrine tumors.

Cluster of many small cysts

Serous cystadenomas.

Calcified scar and enhancement of the internal septa

Serous cystadenomas.

Enhancement of the internal septa

Oligocystic serous cystadenoma.

Large cysts and lacks internal enhancing soft-tissue components.

Imaging features overlap with mucinous cystadenoma



Degeneration



Degeneration

•Mucinous Nonneoplastic Cysts.

•Mucinous Cystadenomas.

•Mucinous Cystadenocarcinoma.

•Pancreatic IPMNs.

Mucinous Nonneoplastic CystsMucinous Nonneoplastic Cysts

Nonneoplastic cysts. No neoplastic potential.

Mucin Containing Cyst

Mucinous differentiation of the epithelial lining cyst. No ductal communication. Lack the surrounding ovarian stroma . No cellular atypia, or the papillary projections.

Mucinous Nonneoplastic CystsMucinous Nonneoplastic Cysts

MRI FindingsMRI Findings Typically small and unilocular or thinly

septate. Internal SI of simple fluid. No enhancing soft-tissue components.


Mucinous Nonneoplastic CystsMucinous Nonneoplastic CystsMucin Containing Cyst

DDx with mucinous cystadenomas.

May be indistinguishable, especially if the cyst is

large and has a thick wall.

Mucinous cystadenomas

Mucinous Nonneoplastic Cysts


Mucinous nonneoplastic pancreatic cyst .

Bi-lobed, smoothly marginated cyst No enhancing soft-tissue elements.

Mucinous CystadenomasMucinous Cystadenomas

10% of pancreatic cystic neoplasms. Majority (>95%) found in women (mean

age, 47 years). Malignant potential cyst.


sampling of the cyst lining must be performed

Mucinous CystadenomasMucinous Cystadenomas

Typically involve body or tail of the pancreas.

Thickened walls, lined by mucin-producing columnar epithelium.

Presence of a surrounding ovarian-type stroma.

No communicate with the pancreatic ductal system.


Mucinous CystadenomasMucinous CystadenomasMRI FindingsMRI Findings Unilocular or mildly septate cystic lesion. Thicked and delayed enhanced wall. Contained fluid : typically mucin filled

More common - simple fluid SI Less common - Increased T1 SI

Often internal septal enhancement. Presence of internal enhancing soft tissue

elements is indicative of carcinoma.



Mucinous cystadenoma.

A single large lobulated cyst without internal enhancing soft-tissue elements.


Mucinous cystadenoma.

A rounded thick-walled cystic structure with thickened enhancing septa.

Mucinous CystadenocarcinomasMucinous Cystadenocarcinomas Older on average than those with diagnosis of

mucinous cystadenoma Progression from cystadenoma to

cystadenocarcinoma

Mucinus cyst with surrouding ovarian type stoma.

Invasive carcinomatous elements.


MRI Findings:MRI Findings: Large complex cysts. Intracystic enhancing soft tissue.

Mucinous CystadenocarcinomasMucinous CystadenocarcinomasMucin Containing Cyst

In a retrospective review of 163 resected In a retrospective review of 163 resected mucinous cysts with surrounding mucinous cysts with surrounding

ovarian-type stromaovarian-type stroma

17.5% of the cysts contained elements of invasive carcinoma at histologic analysis.

All of the lesions with an invasive carcinomatous component had a size of 4 cm or more and demonstrated soft-tissue nodularity.

Hence, any enhancing soft tissue within a cystic neoplasm depicted on MR images is considered an indication for resection.


Mucinous cystadenocarcinoma.

A large, complex cystic lesion with enhancing mural soft-tissue elements.

Pancreatic IPMNsPancreatic IPMNs Intraductal papillary mucinous neoplasms Most frequently in men (mean age, 65 years).

Noninvasive neoplasms with varying degrees of epithelial dysplasia.

Foci of carcinoma in situ. Frank invasive adenocarcinoma.


Pancreatic IPMNsPancreatic IPMNs Mucinous transformation of the pancreatic

ductal epithelium. Usually demonstrates papillary projections. Involves the main pancreatic duct or isolated

side branches. Main duct: 60%–70% invasive carcinoma Side branches: 22% foci of carcinoma.

Frequently multifocal, and 5%–10% involve the entire pancreas


Pancreatic IPMNsPancreatic IPMNsERCPERCP Excessive mucin production results in

cystic dilatation of the pancreatic duct. Possibly,spillage of mucin from the

ampulla of Vater : a classic finding at endoscopic retrograde cholangiopancreatography.


Pancreatic IPMNsPancreatic IPMNsMRI finding: MRI finding: Modality of choice Cyst with ductal communication. Main pancreatic duct dilatation or dilatation of

multiple side branches. Adenocarcinoma in association with an IPMN.

Enhancing soft-tissue nodularity Size more than 3.5 cm Thick walls.



IPMN with involvement of the main pancreatic duct. .

Diffuse dilatation of the main pancreatic duct with a focal cystic lesion.The lesion communicates with the distended main pancreatic duct.


IPMN with involvement of the side-branches.

Focal dilatation of ductal side-branches in the pancreatic head.


Invasive adenocarcinoma in association with an IPMN.

A complex cystic lesion with ductal communication and enhancing soft tissue component.



Degeneration

•Mucinous Nonneoplastic Cysts.

•Mucinous Cystadenomas.

•Mucinous Cystadenocarcinoma.

•Pancreatic IPMNs.



Degeneration

Lymphoepithelial CystsLymphoepithelial Cysts Rare benign pancreatic cysts. The imaging findings are not well described in

the literature. Most common: in men (mean age, 55 years)

The cysts are lined by squamous epithelium and surrounded by dense lymphoid tissue.

Their MR appearances vary: unilocular or multilocular.



Degeneration



Degeneration

Ductal adenocarcinoma with cystic features

Pseudopapillary tumors of the pancreas

Cystic neuroendocrine tumors

Ductal adenocarcinoma Ductal adenocarcinoma with cystic featureswith cystic features

The most common pancreatic neoplasms. (90%)

The most lethal tumor of the pancreas. (5-year survival of less than 3%).

Predominantly solid. 8% cyst like features:

cystic degeneration, retention cysts, and attached pseudocysts.

Solid Pancreatic Tumor with Cystic Degeneration


Usually infiltrative growth pattern. Obstruction of the pancreatic duct or

CBD. Invasion of adjacent vasculature.



MRI Findings:MRI Findings: Infiltrative soft-tissue lesion. Delayed enhancement (contrast material

gradually seeps into the tumor interstitium) Ductal obstruction. Complex cystic areas within or adjacent to the

primary soft-tissue lesion Pseudocysts, internal tumor necrosis, or side-

branch ductal obstruction.



DDx Contain enhancing soft tissue and DDx Contain enhancing soft tissue and cystic components:cystic components:

Ductal Adenocarcinomas with Cystic Features. Infiltrative pattern of the primary tumor. Combined with ductal obstruction and vascular

invasion

Cystic neoplasms such as solid pseudopapillary tumor and mucinous cystadenocarcinoma.



Ductal adenocarcinoma with cystic changes.

A poorly vascularized infiltrative tumor with a central necrosis and pseudocyst.


Ductal adenocarcinoma with cystic changes.

A pancreatic tumor obstructed pancreatic and common bile duct with distention of the pancreatic duct side-branches.

Solid Pseudopapillary TumorsSolid Pseudopapillary Tumors Solid and cystic papillary epithelial neoplasm

of the pancreas. Papillary cystic neoplasm.

Uncommon lesions. Predominantly in women (mean age, 28

years). Low-grade malignant potential.

The cellular lineage remains uncertain: Epithelial VS neuroendocrine.


Solid Pseudopapillary TumorsSolid Pseudopapillary Tumors

MRI Findings:MRI Findings: Predominantly solid. Well circumscribed increased T2 signal

intensity. Gradual uniformly enhancing soft-tissue. Cystic components - secondary to tumor

degeneration. Hemorrhage - common


Solid Pseudopapillary TumorsSolid Pseudopapillary Tumors

DDx DDx Neuroendocrine tumor Mucinous

cystadenocarcinoma.


However, because all three entities require surgical

resection, their preoperative differentiation may not

be important in the clinical setting.

Solid pseudopapillary tumor of the pancreas.

A gradual enhancing solid tumor with internal hemorrhage.


Solid pseudopapillary tumor of the pancreas.

varying degrees of cysticdegeneration


Cystic Neuroendocrine TumorsCystic Neuroendocrine Tumors

Occur in adults (mean age, 53 years) without sex predilection.

Neuroendocrine tumors - Typically solid and well vascularized.

Cystic change - Uncommon.Secondary to tumor degeneration



Neoplastic neuroendocrine cells lining the cyst periphery



MRI Findings:MRI Findings: Well

circumscribed Avidly rim

enhacement in arterial phase.


A patient with a cystic neuroendocrine tumor is significantly

more likely tohave an underlying multiple

endocrine neoplasiasyndrome than a patient with a

uniformly solidneuroendocrine tumor.

Cystic neuroendocrine tumor.

A well define cyst with avidly enhancing thickening rim on arterial phase image.




Degeneration

Ductal adenocarcinoma with cystic features

Pseudopapillary tumors of the pancreas

Cystic neuroendocrine tumors



Degeneration

ConclusionsConclusions Common incidental finding in cross-

sectional imaging.

Neoplastic VS Nonneoplastic processes.

MRI is the best modality for evaluating pancreatic cyst.Good soft-tissue contrast and good to

depiction of pancreatic ductal system.

Which of the following modalities is optimal for depicting internal complexity of a pseudocyst?

A) MR imaging. B) Radiography. C) Multidetector CT. D) Endoscopic retrograde

cholangiopancreatography.

Which of the following cystic lesions of the pancreas is the most common overall?

A) Solid pseudopapillary tumor.B) Mucinous cystadenoma.C) Pseudocyst.D) Lymphoepithelial cyst.

Which of the following imaging methods best depicts vascularized soft tissue within a pancreatic cystic lesion?

A) Unenhanced and contrast-enhanced 3D MR imaging with T1-weighted sequences.

B) Axial thin-section 3D MR cholangiopancreatography.

C) Axial single-shot T2-weighted MR imaging. D) Coronal thick-slab MR

cholangiopancreatography.

Which of the following clinical or demographic characteristics is most common among patients with mucinous cystadenomas?

A) Presence of chronic or recurrent pancreatitis. B) Presence of von Hippel-Lindau disease. C) Age of less than 20 years. D) Female sex.

Which of the following pancreatic cystic lesions may occur in the setting of von Hippel-Lindau disease?

A) Mucinous cystadenoma.B) Serous cystadenoma.C) Ductal adenocarcinoma with cystic features.D) IPMN.

Which of the following characteristics of an IPMN is most commonly associated with invasive carcinoma?

A) Localization to a pancreatic duct side branch. B) Involvement of the main pancreatic duct. C) Absence of soft-tissue nodularity. D) Size of less than 3 cm.

Which of the following pancreatic cystic lesions does not include a vascularized soft-tissue component?

A) Mucinous cystadenocarcinoma. B) Solid pseudopapillary tumor. C) Mucinous nonneoplastic cyst of the pancreas. D) Ductal adenocarcinoma with cystic features.

Which of the following statements does not accurately characterize cystic pancreatic neuroendocrine tumors?

A) They are rarer than solid neuroendocrine tumors.B) They are more commonly associated with multiple endocrine neoplasia than are solid neuroendocrine tumors.C) They may include a vascularized soft-tissue component.D) They usually demonstrate poor margination and an infiltrative growth pattern.

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