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5 December 2012 - Case of the Week #260

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Case of the Week #260

Clinical History:
A 75 year old woman was three years status post lumpectomy and radiation therapy for invasive ductal carcinoma of the breast. CT scan incidentally revealed a 2.2 X 1.7 X 1.5 cm nodular lesion in the inferior tip of the right hepatic lobe. PET demonstrated evidence of increased metabolism within the mass. No lymphadenopathy or organomegaly was detected. There was no lymphocytosis in the peripheral blood, and serology for HBV and HCV infection was negative. CT guided needle core biopsy was performed.

Images:


CT scan


Fine needle aspirate

           
Micro images

What is your diagnosis?































Diagnosis:

Primary low-grade hepatic B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type

Discussion:

Immunostains were performed (only some images are shown below):


Left to right: CD20, bcl2, Ki-67


Left to right: CD5, CD10, Cyclin D1

The H&E sections show a dense, atypical lymphoid infiltrate with sheets of monomorphous small, centrocyte-like, mature lymphocytes. Occasional lymphoepithelial lesions with hepatocytes or bile ducts are seen. The lymphocytes have scant cytoplasm, round nuclei and condensed chromatin. Mitotic figures are difficult to find. No large atypical cells are seen. Focal intrahepatic and canalicular cholestasis is appreciated. The liver parenchyma and entrapped bile ducts are unremarkable. There is no evidence of metastatic carcinoma.

The atypical lymphoid proliferation is diffusely positive for B cell markers (CD20 and CD79a) with coexpression of Bcl2 and kappa light chain restriction, and negative for Bcl6, CD3, CD5, CD10, CD23, CD30, CD43 and CyclinD1. The cell proliferation index marker Ki-67 is positive in 10-15% of cells, consistent with a low grade process. Cytokeratin 7 stain highlights the residual bile ducts and lymphoepithelial lesions. The morphology and immunophenotypical features are typical of a low grade small B cell lymphoma, favoring marginal zone origin of mucosa associated lymphoid tissue (MALT) type.

Primary hepatic lymphomas are uncommon, and most reported cases have been high grade B cell lesions. Primary hepatic MALT lymphoma is an extremely rare event. Of the cases reported, most of them are incidental findings, with tumors ranging from 2 to 7.5 cm in diameter. Chronic viral hepatitis and primary biliary cirrhosis (PBC) are considered to be the underlying disease in some case reports. Primary hepatic MALToma is usually treated with local resection and shows better prognosis.

References:

1. Osborne BM, Butler JJ, Guarda LA. Primary lymphoma of the liver. Cancer 1985;56:2902.

2. Isaacson PG, Banks PM, Best PV, McLure SP, Muller-Hermelink HK,Wyatt JI. Primary low-grade hepatic B-cell lymphoma of mucosa-associated lymphoid tissue (MALT)-type. Am J Surg Pathol 1995;19:571.

3. Prabhu RM, Medeiros LJ, Kumar, et al. Primary hepatic low grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) associated with primary biliary cirrhosis. Mod Pathol 1998;11:404.

Nat Pernick, M.D., President
and Palak Thakore, Associate Medical Editor
PathologyOutlines.com, Inc.
30100 Telegraph Road, Suite 408
Bingham Farms, Michigan (USA) 48025
Telephone: 248/646-0325
Email: NatPernick@Hotmail.com
Alternate email: NatPernick@gmail.com