Adenocarcinoma Arising in a Remnant Rectum after Proctocolectomy (Ileo-anal Canal Anastomosis) for Ulcerative Colitis

We report a case of cancer in the rectal remnant 8 years following a near total proctocolectomy for ulcerative colitis. A 71-year-old man had undergone a subtotal colectomy in November 1998, following an additional proctocolectomy and reconstruction by ileo-anal canal anastomosis in August 2000. The resected specimen of the primary procedure showed a diffuse severe inflammation throughout the rectosigmoid and sigmoid colon but revealed no dysplastic lesions in the rectum. It also included adenomas in the sigmoid colon. Eight years later, he developed a macroscopically type 3 cancer in the remnant rectum just caudal to the ilio-anal canal anastomosis. Pathology revealed a node-negative stage I rectal cancer of moderately-differentiated tubular adenocarcinoma invading the muscularis propriae. Although such cases are rare, the possibility of the late development of cancer arising from the remnant rectal mucosa after near-total proctocolectomy and ileo-anal canal anastomosis.