A Case of Abscessing Ileocecal Monomorphic Epitheliotropic Intestinal T-cell Lymphoma.

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), previously referred to as enteropathy-associated T-cell lymphoma (EATL) type II, is a rare type of intestinal extranodal T-cell lymphoma that arises from intraepithelial T-lymphocytes of the intestinal mucosa. Here, we report a case of MEITL with an unusual localization in the ileocecal region complicated by an adjacent abscess and perforation of colon ascendens in a 65-year-old male. The patient was admitted to the hospital with acute abdominal pain. A computed tomography (CT) scan revealed a circumferential cecal wall thickening. Following an initial period of improvement, the patient's condition deteriorated due to bowel perforation and inflammatory processes in the abdominal cavity. A right hemicolectomy and a latero-lateral ileo-transverse anastomosis were performed, and the subsequent histological examination revealed a population of monomorphic lymphoid blast cells with hyperchromatic nuclei, coarse chromatin, and irregular nuclear outline, forming cellular aggregates and infiltrating the intestinal wall from the submucosa to the serosa. The tumor cells were small to medium in size and demonstrated marked epitheliotropism. Immunohistochemistry (IHC) showed intense cytoplasmic CD45, membrane-cytoplasmic CD3, cytoplasmic Bcl-2, CD8, and membrane CD56 expression. The proliferation index Ki-67 was evaluated as high, being positive in more than 70% of the tumor cells. The patient died 39 days after the initial onset of symptoms.