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5 February 2015 - Case of the Week #341

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Case of the Week #341

Clinical History:
A 60 year old woman was found to have multiple, slow growing liver lesions, and underwent a liver biopsy.

Micro images:


What is your diagnosis?

Epithelioid hemangioendothelioma


Immunostains were performed:

Left to right: CD34, CD31, HepPar1

The H&E sections show an intrasinusoidal and intravascular infiltrative growth pattern (figure 1) with intraluminal tufting (figure 2) of epithelioid and spindle cells with surrounding compressed hepatocytes with steatosis (figure 3). Figure 4 shows epithelioid cells with intracytoplasmic vacuoles ("signet ring cells"). The immunostains show that the epithelioid cells are strongly positive for CD34 and CD31, and although the hepatocytes are immunoreactive for HepPar1, the intrasinusoidal proliferation is HepPar1 negative.

Epithelioid hemangioendothelioma is a low grade, slow growing, malignant endothelial neoplasm which typically occurs in middle aged patients, and is more common in women (60%). Most cases are due to t(1;3)(p36.3;q25), which produces the fusion gene WWTR1-CAMTA1 (Am J Surg Pathol 2001;25:684, Genes Chromosomes Cancer 2011;50:644). These tumors rarely produce the YAP1-TFE3 fusion gene (Genes Chromosomes Cancer 2013;52:775).

Grossly, epithelioid hemangioendothelioma is often multifocal, grey-white and firm, with variable calcification. Histologically, it has a characteristic zonal pattern with peripheral tumor cells growing along preexisting sinusoids and terminal hepatic venules, with sinusoidal proliferation and intraluminal polypoid or tuft-like projections. Some epithelioid cells show rudimentary intracytoplasmic lumina. Cytologically, the atypical cells have moderate eosinophilic cytoplasm, relatively large hyperchromatic and irregular nuclei and small inconspicuous nucleoli. The surrounding hepatocytes show compression and focal steatosis. The midzone shows sinusoidal obliteration with marked atrophic hepatocyte plates in a fibrous and myxochondroid stroma, with variable calcification (Clin Mol Hepatol 2013;19:315). Tumor cells are immunoreactive for vascular markers CD31, CD34 and D2-40. They are also positive for CD10.

The differential diagnosis includes intrahepatic cholangiocarcinoma, angiosarcoma (rapid growth, highly cellular with ectatic neoplastic vessels exhibiting congestion and hemorrhage, usually marked atypia, extramedullary hematopoiesis, usually no sclerosis), sclerotic hepatocellular carcinoma and sclerosed hemangioma (well circumscribed, no venous invasion, no atypia).

Epithelioid hemangioendothelioma typically has indolent behavior. Treatment options are surgical resection with curative intent (World J Gastroenterol 2014;20:7049, HPB (Oxford) 2010;12:546), or liver transplantation if multiple tumors are present.

Nat Pernick, M.D., President
and Shivani Thakore, Associate Medical Editor
PathologyOutlines.com, Inc.
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Bingham Farms, Michigan (USA) 48025
Telephone: 248/646-0325
Email: NatPernick@Hotmail.com
Alternate email: NatPernick@gmail.com