2019 Volume 39 Issue 5 Pages 953-957
Ulcerative colitis (UC) is known to be associated with a high probability of having colorectal adenocarcinoma, but complication with a malignant lymphoma is rare. We report herein on a case of intestinal obstruction due to a malignant lymphoma of the rectum in a patient with a long–term history of untreated UC. A 66–year–old man had been diagnosed as having UC about 30 years before, but he had never been treated for it. He was admitted to our hospital with melena and right lower abdominal pain. Abdominal CT showed a mass with wall thickening of the rectum, and colonoscopy revealed a type 3 tumor of the rectum and loss of the typical mucosal vascular pattern starting at the anal verge. We performed a Hartmann operation for a suspected rectal cancer with UC. The tumor was adherent to the peritoneum, right vas deferens, and right ureter, and infiltration was suspected. On histopathological examination, the tumor was diagnosed as being a diffuse large B–cell lymphoma. Chronic inflammation and immunosuppressive drugs have been reported to increase the incidence of malignant lymphoma in patients with UC. A malignant lymphoma can also be considered when intestinal obstruction has developed in patients with UC although diagnosis is difficult.
