Biliary Cystadenocarcinoma

Published on 19/07/2015 by admin

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Last modified 19/07/2015

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 Tumor is encapsulated

image Recurs after incomplete excision
image Variable MR signal intensity locules depending on content of cystic fluid
• Malignant potential to develop into cystadenocarcinoma even after years of stability

TOP DIFFERENTIAL DIAGNOSES

• Hemorrhagic or infected hepatic cyst

image No enhancement of nodules or septa
• Hepatic pyogenic abscess

image Cluster sign: Small abscesses aggregate, sometimes coalesce into single large septate cavity
image Rim of abscess locules will enhance
• Cystic metastases

image Show debris and mural nodularity
• Hydatid (echinococcal) disease

CLINICAL ISSUES

• Usually occurs in middle-aged women

image > 90% in women

DIAGNOSTIC CHECKLIST

• Large, well-defined, homogeneous or heterogeneous, complex cystic mass with septations and nodularity

image Almost always solitary
image Enhancing mural nodules suggest malignancy
• May mimic hemorrhagic or infected hepatic cyst
image
(Left) Graphic shows a lobulated complex cystic mass with a vascularized wall and septa.

image
(Right) Axial CECT in a middle-aged woman shows a complex cystic mass with lobulated margins and an enhancing wall and septa image. These findings in a patient with no other known tumor could be considered sufficiently diagnostic of a biliary cystadenoma to warrant resection without further evaluation.
image
(Left) Axial T1WI MR in a middle-aged woman shows a classic multiseptate, cystic, hepatic mass image with cyst contents having features characteristic of fairly simple fluid. There is slight heterogeneity of the signal that varies between some of the cyst compartments.

image
(Right) Axial T2WI MR in the same patient shows the bright signal of fluid content within the large septate mass.

TERMINOLOGY

Synonyms

• Bile duct cystadenocarcinoma, hepatobiliary cystadenoma

Definitions

• Rare, malignant or premalignant, unilocular or multilocular, cystic tumor

image May arise from intrahepatic bile ducts (IHBDs) within liver (common site)
image Very rarely from extrahepatic biliary tree or gallbladder

IMAGING

General Features

• Best diagnostic clue

image Complex, multiloculated, cystic mass in liver, often with septations and mural calcifications
• Location

image Right lobe (55%), left lobe (29%), both lobes (16%)
image Arising from

– Intrahepatic biliary ducts (83%)
– Extrahepatic bile ducts (13%)
– Gallbladder (0.02%)
• Size

image 1.5-25 cm in diameter

– Usually large at time of diagnosis if symptomatic
• Key concepts

image Biliary cystadenocarcinoma

– Malignant transformation of benign biliary cystadenoma
– Typically solitary tumor; usually multilocular, but sometimes unilocular
– Tumor is encapsulated
– Usually seen in middle-aged women
– Recurs after incomplete excision
image Benign biliary cystadenoma

– Probably congenital in origin due to presence of aberrant bile ducts
– Recurs after incomplete excision
– Malignant potential to develop into cystadenocarcinoma even after years of stability
image Benign and malignant lesions together account for only 5% of all intrahepatic lesions of bile duct origin
image Microcystic cystadenoma variant

– Composed of multiple small cysts
– Glycogen-rich cystadenoma
– Typical papillary and mesenchymal stromal features are not seen
– Lined by single layer of cuboidal epithelial cells
– Resembles serous microcystic adenoma of pancreas in pathology and on imaging

CT Findings

• NECT

image Large, well-defined, homogeneous, hypodense, water-density mass

– Some are heterogeneous (cystic and hemorrhagic areas)
image Cystadenocarcinoma: Septations and nodularity
image Cystadenoma: Septations without nodularity
image Mural or septal calcifications are common
image Biliary dilatation (due to pressure effect) of IHBDs

– Biliary obstruction considered to favor malignant tumor
• CECT

image Multilocular tumor

– Nonenhancing cystic spaces
– Enhancement of internal septa, capsule, and nodules
– Enhancement of papillary excrescences
– Mural or septal calcifications

image Less commonly, “honeycomb” or “sponge” appearance (microcystic variant)
– Uncommonly has metastases or adenopathy at initial diagnosis
image Unilocular tumor

– Large or small nonenhancing cystic space
– Enhancement of outer capsule and papillary excrescences
– Fine mural calcifications

MR Findings

• T1WI

image Variable signal intensity locules depending on content of cystic fluid
image High signal intensity (mucoid or hemorrhagic fluid)
image Low signal intensity (serous fluid)
image Septal or mural calcifications: Hypointense
• T2WI

image High signal intensity (serous fluid)
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