An enteropathy-associated T-cell lymphoma arising from the small intestine, most commonly the jejunum or ileum. Patients usually present with abdominal pain, often associated with intestinal perforation. There is often a history of celiac disease. The lymphoma cells are usually medium-sized to large and form an ulcerating mucosal lesion with invasion of the small intestinal wall. Villous atrophy is present in the adjacent small intestinal mucosa. In a minority of cases the lymphoma cells are medium-sized and form a monomorphic infiltrate. [ NCIT:P378 ]