Monomorphic epitheliotropic intestinal T-cell lymphoma may mimic intestinal inflammatory disorders.

There is a significant overlap between intestinal lymphoproliferative disorders (LPDs) and inflammatory conditions of the intestine, including inflammatory bowel disease (IBD), in clinical, endoscopic, or histologic appearance, leading to diagnostic challenges. We report two cases of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) that were initially considered to be ulcerative colitis (UC) and lymphocytic colitis, respectively. Both patients presented with diarrhea and abdominal pain. Colonoscopy revealed hyperemia and scattered shallow ulcerations in the colon, without obvious mass. Microscopically, the first case exhibited features of active chronic colitis. The second case exhibited features mimicking lymphocytic colitis and ileitis. Correct diagnosis of lymphoma was established when the cases were received as consultation, with additional ancillary tests performed. Being familiar with the endoscopic features and unusual histologic patterns of MEITL described here is critical for prompt diagnosis and timely treatment, which may be conductive to a better prognosis.