Gastrointestinal involvement by mantle cell lymphoma observed by endoscopy: A case report

INTRODUCTION: Mantle cell lymphoma (MCL) is a subtype of non-Hodgkin B-cell lymphoma, accounting for 6% of all non-Hodgkin lymphoma. The typical appearance of intestinal MCL is multiple lymphomatous polyposis, whereas presentation as protruding lesions is uncommon. We herein report the case of a 64-year-old male patient who was admitted to our hospital with epigastric pains. On endoscopy, submucosal neoplasma were identified in the gastric antrum, the duodenal bulb, and the rectum. On endoscopic ultrasonography (EUS) (OLYMPUS EUS EU-ME2, Miniprobe sonography), the lesions were homogeneously hypoechoic and originated from the submucous layer or muscularis mucosa. Pathological examination of biopsied specimens from the lesions of the rectum revealed diffuse lymphomatous proliferation and dense infiltration by monomorphic and small cleaved cells with irregularly shaped nuclei. On immunohistochemistry, the cells were positive for cyclin D1, CD20, CD21, SOX-11, and Bcl-2, but negative for CD3 and CD10; these findings were compatible with a diagnosis of MCL. CONCLUSION: The EUS characteristics initially led to the suspicion of digestive neuroendocrine tumors, since MCL presenting as submucosal tumors on EUS is rarely reported. We herein present this case to suggest clinician to include MCL in the differential diagnosis of submucosal intestinal lesions, as early diagnosis and timely treatment may improve patient prognosis.