Colon cancer in rectal bladder.

A large number of patients have been reported with colon cancers following ureterosigmoidostomy, created after total cystectomy. However, there have been few reports of cancer in rectal bladder created instead of ureterosigmoidostomy to reduce the risk of cancer development. We report a case of colon cancer that developed in the rectal bladder 6 years after the operation. A 77-year-old man presented with blood in stools. Colonoscopy revealed a cancer adjacent to the urine inlet to the colonic lumen in rectal bladder. At laparotomy. the cancer was recognized in the rectal bladder. with invasion to the pubic bone. A palliative resection of the rectal bladder, and creation of sigmoid colostomy and ileal conduit were performed. Histologic examination confirmed moderately differentiated adenocarcinoma, which was considered to have originated from the colonic mucosa in the rectal bladder. Colonic mucosa has an increased risk of cancer development after continuous exposure to urine. It is important for gastroenterologists to perform surveillance colonoscopy in patients with urinary diversion into the colon.