18 January 2007 Case of the Week #70

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We thank Dr. Hanni Gulwani, Sir Ganga Ram Hospital, New Delhi (India) for contributing this case. We invite you to contribute a Case of the Week by sending an email to NPernick@PathologyOutlines.com with microscopic images (any size, we will shrink if necessary) in JPG or GIF format, a clinical history, your diagnosis and any other images (gross, immunostains, EM, etc.) that may be helpful or interesting. We will write the discussion (unless you want to), list you as the contributor, and send you a check for $35 (US) for your time after we send out the case. Please only send cases with a definitive diagnosis.

Case of the Week #70

Clinical history

A 47 year old woman presented with pain in the right hypochondrium (upper lateral abdomen). CT scan showed a cystic space occupying lesion in the liver measuring 6 x 5 cm, which was excised.

Micro images: image #1-low power; #2-low power; #3-high power; #4-high power; #5-high power; #6-high power; #7-high power; #8-CA19-9; #9-progesterone receptor

What is your diagnosis?

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Diagnosis:

Biliary mucinous cystadenoma of liver

Discussion

The low power images show a cystic, multiloculated lesion with adjacent normal liver (L). The high power images show a cyst lined by benign mucinous columnar epithelium. Image 7 shows ovarian-type stroma. The epithelium is immunoreactive for CA 19-9 and the stromal nuclei stain for progesterone receptor.

Biliary cystadenomas represent 5% of hepatic solitary cysts. Over 90% occur in women, with a mean age of 45 years. Although most (84%) are intrahepatic, they also occur within the common bile duct (6%), hepatic ducts (4%), cystic duct (4%) and gallbladder (2%). They may be associated with polycystic liver disease or abnormal hepatobiliary anatomy.

They are usually encapsulated, large (mean diameter 15 cm), mucinous and multilocular, and may contain up to several liters of fluid. The inner lining is smooth, with few trabeculations or polypoid cystic projections. The presence of nodules of solid tissue suggests malignancy, which occurs in up to 25% of cases.

Histologically, they are lined by a single layer of columnar-cuboidal mucinous epithelium with basal nuclei and apical mucin. Tumors in women have spindle cell ovarian type stroma, similar to that in pancreatic mucinous cystic neoplasms. The spindle cells may contain fat and smooth muscle. Although typically bland, there may be dysplastic foci. The uncommon serous tumors have clear, glycogen-rich cytoplasm, but no mucin or spindle cell stroma.

The epithelium in biliary cystadenomas is immunoreactive for cytokeratin, EMA, CA19-9 and CEA. The stromal cells are immunoreactive for muscle specific actin, vimentin and usually for estrogen and progesterone receptor (Dig Dis Sci 2006;51:623)

These tumors are usually slow growing, and have a good prognosis after surgical excision.

The differential diagnosis includes borderline tumors (with high grade dysplasia and complex architecture) and invasive tumors, which must be ruled out by taking numerous sections.

Additional references: World J Gastroenterol 2006;12:6062 (case report)

Nat Pernick, M.D., President
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