Sigmoid adenocarcinoma complicating ureterosigmoidostomy.

A 31-year-old man who died of metastatic adenocarcinoma of the sigmoid colon had undergone bilateral ureterosigmoidostomy for exstrophy of the bladder 20 years earlier. The patient never underwent a colonoscopy. Neoplastic transformation at the ureterosigmoid anastomosis must be considered as a possible severe complication, and therefore, periodic follow-up of these patients is mandatory.