Lymphoid hyperplasia of the large intestine: A case report with immunohistochemical and gene analysis

A case of lymphoid hyperplasia arising in the large intestine of a 54-year- old woman is described. Barium enema X-ray and colonoscopic examination rev ealed multiple small polyps in the right side of the colon. Pathological fi ndings from forceps biopsy revealed similar features to a mucosa-associated lymphoid tissue (MALT) lymphoma. A right hemicolectomy with mesenteric lym ph node dissection was carried out. Histological sectioning demonstrated hy pertrophic lymphoid follicles with well-formed germinal centers. Occasional ly, lymphocytes infiltrated the crypts, in a way similar to that found in l ymphoepithelial lesions, which was suggestive of a MALT lymphoma diagnosis. Cryptitis was also observed in the lamina propria. Immunohistochemically, proliferating lymphocytes were positive for CD20 (L26) and negative for CD4 5RO (UCHL-1). Analyses of immunoglobulin gene (IgHJH) rearrangement could n ot detect any monoclonality in these cells. These findings suggested that t he present case should be categorized as lymphoid hyperplasia rather than l ymphoma.