Gastrointestinal mantle cell lymphoma (MCL) is an aggressive subtype of B-cell lymphoma accounting for 1 % to 2 % of non-Hodgkin lymphomas. Patients usually present with lymphadenopathy, bone marrow, and extranodal involvement. The commonest gastrointestinal (GI) manifestation is multiple lymphomatous polyposis, in which multiple lymphoid polyps are present in the GI tract [1, 2]. The ileocecal region is the commonest site involved. GI symptoms include pain, obstruction, diarrhea, or hematochezia. Multiple lymphomatous polyposis may also be seen in marginal B cell lymphomas, mucosa associated lymphoid tissue (MALT), and follicular lymphomas. Despite prompt remission, prognosis remains poor in view of increased relapse rates. Median survival is 3 to 5 years. Our patient presented with bloody diarrhea for 6 weeks. Colonoscopy revealed diffuse submucosal polypoidal lesions (Fig. 1, Supplemental Fig. S1) and upper GI endoscopy revealed similar multiple polypoidal lesions in the stomach (Supplemental Fig. S2) and duodenum. CT scan abdomen (Supplemental Fig. S3a, b) revealed nodular lesions involving the entire GI tract with intraabdominal lymphadenopathy. Biopsies from the nodules revealed malignant B-cell lymphoma with immunohistochemistry positive for CD20, CD5, and cyclin D1 (Supplemental Fig. S4.) He received rituximab-based chemotherapy which resulted in significant tumor regression (Supplemental Fig. S5) and prompt symptomatic palliation.

Fig. 1
figure 1

Pan-colonic lymphomatous polyposis noted on colonoscopy

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