Gastrointestinal Pathology- Clinicopathologic Correlation in Mucosal Biopsy

Case #3 (question #4 and #5):

A 65 year-old lady with abdominal pain. Endoscopy revealed gastric erosions and mucosal granularity. Representative images are illustrated below:

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Question No. 4. The Answer is: (C) Reactive gastropathy.

Discussion: The gastric biopsy shows dense and diffuse proliferation of small to intermediate sized lymphocytes with coarse chromatin and irregular nuclear contours. Numerous lymphoepithelial lesions with neoplastic lymphoid cells causing marked glandular destruction, and focal regions of monocytoid lymphocytes are also seen (Panel B and C). These features are characteristic of extranodal marginal zone B-cell lymphoma (MALT lymphoma). The differential diagnosis includes other types of lymphoma such as follicular lymphoma, and small lymphocytic lymphoma/chronic lymphocytic leukemia. The distinction between florid gastritis and MALT lymphoma may be difficult as in both reactive and neoplastic processes, lymphoid follicles may be present.

Question No. 5. The Answer is: (C) CD20+, CD79a+, CD5-, CD10-, CD23-, CD43+/-, CD11c+/- (weak).

Discussion: The typical immunophenotype for MALT lymphoma is : CD20+, CD79a+, CD5-, CD10-, CD23-, CD43+/-, CD11c+/- (weak). The neoplastic cell population in MALT lymphoma comprises small B-cells including marginal zone cells, monocytoid cells, small lymphocytes, and scattered immunoblast and centroblast-like cells. It comprises 7 to 8% of all B-cell lymphomas and up to 50% of primary gastric lymphomas. The median age of presentation is 61 years. Currently, there is no specific immunophenotypic marker for MALT lymphoma. The demonstration of immunoglobulin light chain restriction is important in distinction from benign lymphoid aggregates. Lack of CD5 is useful in distinguishing from mantle cell and small lymphocytic lymphomas. Lack of CD10 is useful in the differential with follicular lymphomas. In many cases, there is a history of chronic inflammatory state, including Helicobacter pylori gastritis (in over 90% of gastric MALT lymphomas), Hashimoto thyroiditis, and Sjögren syndrome. It has an indolent natural course. Protracted remission may follow H. pylori eradication.