Primary marginal zone B-cell lymphoma of gastrointestinal tract presenting as multiple lymphomatoid polyposis

Abstract

Dear Editor: Multiple lymphomatous polyposis (MLP) is a distinctive pattern of gastrointestinal lymphoproliferative lesion characterized by multiple nodular or polypoid tumors infiltrating segments of the intestine. MLP is usually seen in mantle cell lymphoma (MCL). However, other lymphoproliferative diseases, including marginal zone B-cell lymphoma (MZL), can also be presented as MLP. Although MZL is rare in MLP, its differentiation from the more common MCL is clinically significant because of their remarkably different clinical course and prognosis. In this article we present a case of gastrointestinal MZL initially presented as MPL of rectum and then also involving the stomach and duodenum. A 43-year-old woman visited our institution complaining of a 1-month history of lower abdominal pain, constipation, tenesmus, and mild weight loss. Initial sigmoidoscopic examination revealed numerous smallto medium-sized, grape-like polypoid lesions covering the whole rectal mucosa. On barium enema, in addition to the polypoid lesions, there was an asymmetrical luminal narrowing and indentation in upper rectum with widened retrorectal space without mucosal destruction or irregularity. The abdominal computed tomography (CT) scan revealed a 4-cm-sized, oval, and hypodense mass-like lesion within the posterior rectal wall with a thin, hyperdense wall and septated internal structure. The entire rectal wall was also diffusely thickened. The gastroscopic examination also revealed a 2-cmsized, shallow mucosal depression with surrounding mucosal thickening in the midbody, multiple small erosions and healed erosion in the antrum of the stomach, and multiple small polypoid mucosal elevations in the duodenal bulb. Microscopically, the rectal polyps showed a nodular infiltration of lymphoid cells with very distinct patterns of marginal zone involvement around the reactive germinal centers and mantle zones. The majority of infiltrating tumor cells was monocytoid, centrocyte-like cell with clear cytoplasm. There were mixed populations of small lymphocytes and occasional large blasts also. Rare lymphoepithelial lesions (LELs) were observed. Immunohistochemically, the tumor cells were of B-cell origin and positive for CD20, CD79a, and bcl-2 antibodies. CD3and CD5-positive small lymphocytes were seen mainly around the neoplastic B cells. Some B cells were also positive for CD43 antibody. However, the tumor cells were negative for CD23 and cyclin D1. The histological findings of the gastric and duodenal lesions were similar to B. K. Shin . H. Lee . J. Choi . A. Kim . H. Kim . I. Kim (*) Department of Pathology, Korea University Guro Hospital, 80 Guro-dong Guro-gu, Seoul, 152-703 South Korea e-mail: iskim@korea.ac.kr Tel.: +82-2-8186233 Fax: +82-2-8186239