Colonic Mantle Cell Lymphoma with Multiple Lymphomatous Polyposis

A 64-year-old white male with a past medical history of coronary artery disease, hypertension, and diabetes presented for a screening colonoscopy. He had no complaints of hematochezia, nor of any fevers, fatigue, night sweats, or chills. A colonoscopy was performed and revealed diffuse, innumerable sessile sub-centimeter polyps throughout the colon (Fig. 1), as well as a fungating, ulcerated mass arising from the ileocecal valve (Fig. 2). The mass was biopsied and representative samples of the polyps were resected. Pathology revealed mantle cell lymphoma, with the neoplastic lymphocytes staining for CD20 and cyclin D1, but negative for CD3 (Fig. 3, 4). Computed tomography revealed extensive mesenteric and retroperitoneal lymphadenopathy, as well as prominent carinal and hilar nodes. Flow cytometry showed monoclonal CD5positive B cells, and a bone marrow biopsy revealed 40– 50% involvement of the bone marrow by mantle cell lymphoma. A PET scan was performed, and revealed extensive FDG-avid retroperitoneal, mesenteric, iliac, inguinal, and bilateral axillary lymphadenopathy as well as an FDGavid cecal mass. The patient was diagnosed with stage IV mantle cell lymphoma, had a Port-a-Cath placed, and was initiated on rituximab and bendamustine given his comorbidities and poor functional status. Mantle cell lymphomas involving the gastrointestinal tract are rare, accounting for 4–9% of all gastrointestinal B-cell lymphomas [1]. A modified Ann Arbor classification is used for anatomic description of disease extent [2], although functional status and risk stratification using scores, such as the Mantle Cell International Prognostic Index (MIPI), also play a large role in treatment. Multiple lymphomatous polyposis (MLP) is an uncommon type of primary gastrointestinal lymphoma, presenting as multiple lymphomatous polyps throughout the gastrointestinal tract. Although MLP is most commonly seen with mantle cell lymphoma, it has also been