Rare Presentation of Gastrointestinal Mantle Cell Lymphoma

Abstract

Purpose: Mantle cell lymphoma is an uncommon B-cell non-Hodgkin lymphoma, accounting for only 3 to 10% of lymphoma cases. The disease can be aggressive and extranodal involvement is common. The spleen and bone marrow are most frequently affected. Gastrointestinal involvement is less common and when present usually manifests as a symptomatic condition known as multiple lymphomatous polyposis. There are few reports of mantle cell lymphoma presenting as a single polyp or without symptoms. We report the first case of mantle cell lymphoma arising in a tubular adenoma detected by routine colonoscopy in an asymptomatic patient. This is a case of a 67-year-old previously healthy male who presented to an outpatient endoscopy center for his first colonoscopy. Colonoscopy detected four colonic polyps and two small rectal polyps. The rectal polyps were ablated by fulguration and three of the four colonic polyps were determined to be hyperplastic. The remaining polyp revealed a tubular adenoma overlying an atypical lymphoid infiltrate. The lymphoid cells were strongly positive for Cyclin-D1, CD5, CD20, and BCL2 with a small subset showing positivity for CD43. These cells were negative for CD10, CD23, and BCL-6. The histology and immunohistochemistry were consistent with mantle cell lymphoma. Subsequent bone marrow biopsy and staging revealed diffuse disease. The patient was started on aggressive chemotherapy, but was switched to Betamustine due to intolerance. He has undergone four cycles and currently feels well. This is the first report of mantle cell lymphoma presenting in a tubular adenoma of an asymptomatic individual. Our case highlights the need to detect and investigate all atypical lymphoid infiltrates.