A rare case of primary malignant lymphoma of the rectum is reported. An 83-years-old woman complained of hemorrhage on defecation. She was diagnosed as malignant lymphoma of the rectum with the colonoscopy and barium enema. Abdominoperineal resection of the rectum was performed. Histological examination of the resected specimen indicated a malignant lymphoma of the rectum, invaded to the proper muscle. Several immunohistochemical studies proved that the lymphoma was diagnosed as the diffuse large B cell type in REAL classification.
