[Digestive lymphomatous polyposis: study of a case diagnosed by rectal biopsy].

We report a case of gastrointestinal lymphomatous polyposis revealed by a rectal tumor. Numerous polypoid lesions, 5 to 20 mm in diameter, were found at various levels of the gastrointestinal tract. Microscopic examination of gastric, duodenal, colic and rectal specimens led to the diagnosis of small cleaved-cell type lymphoma. The immunohistochemical study showed a monotypic surface staining of the lymphomatous cells with anti-IgM, IgD, kappa, C3b, and CD5 antibodies. This type of lymphoma is rare and presents as multifocal polyposis of the gastrointestinal tract. Only histologic and immunohistologic studies can establish diagnosis. Gastrointestinal lymphomatous polyposis is classified as a low-grade malignant lymphoma, with frequent nodal, hepatosplenic, bone marrow, and blood involvement. Chemotherapy is the appropriate treatment.