A case of mucosa-associated lymphoid tissue lymphoma forming multiple lymphomatous polyposis in the small intestine.

A 50-year old woman suffering from diabetes had a CT scan that revealed a diffuse thickening of small intestinal wall and swollen paraaortic lymph nodes. An esophagogastroduodenoscopy (EGD) confirmed multiple polypoid lesions in the duodenum and small intestine, and conventional histological testing revealed non-specific inflammatory changes. Further examinations including the immunohistochemical profiles of the biopsied specimens led us to diagnose the lesion as a marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type, forming multiple lymphomatous polyposis sequentially spreading from duodenal bulb to terminal ileum. According to Lugano's classification, its staging was clinically diagnosed as stage II. Two courses of a standard CHOP (cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and predonisolone) regimen with rituximab reduced the lesion and the patient had a almost complete response. A 5-year follow-up EGD and histological examinations detected no recurrence of the disease.