Richter's syndrome mimicking chronic colitis. A patient with diffuse histiocytic lymphoma complicating chronic lymphocytic leukemia.

A 62-year-old woman developed diffuse histiocytic lymphoma in the course of chronic lymphocytic leukemia and manifested symptoms mimicking chronic ulcerative colitis. Chronic lymphocytic leukemia may be complicated by the development of lymphoma designated Richter's syndrome. These lymphomas may present in the gastrointestinal tract with signs and symptoms suggestive of chronic inflammatory bowel disease. Initial diagnostic studies, especially barium studies, may yield similar findings. However, histologic findings and clinical course are particularly important in differentiating the disorders.