[A case of adenocarcinoma occurring in the bladder mucosa after a surgical operation for colovesical fistula].

We report a case of adenocarcinoma occurring in the bladder mucosa 6 years after a surgical operation for colovesical fistula due to colonic diverticulitis of the sigmoid colon. The patient was a 76-year-old woman who had undergone a sigmoidectomy and ligation of the colovesical fistula at the age of 70 years. She presented with a complaint of gross hematuria. Cystoscopy and computed tomography revealed bladder cancer at the site of the original colovesical fistula surgery. She underwent transurethral resection of the bladder tumor. Histopathological findings revealed intestinal adenocarcinoma in the urinary bladder. A radical partial cystectomy was subsequently performed because of a positive and involved margin. This tumor may have originated from the bladder mucosa and then replaced by intestinal metaplastic cells that originated from the same initiating event.