Colorectal neoplasm: a rare complication of ureterosigmoidostomy.

A 24-year-old woman had a rectal neoplasm which occurred 20 years after she had undergone ureterosigmoidostomy for exstrophy of the bladder. Only 41 cases of bening or malignant tumours of the large bowel developing after ureterosigmoidostomy have previously been reported in the literature. Adenocarcinoma of the colon is most frequently found and can develop even after urine has been diverted away from the colon. The presenting symptoms are either those of ureteral obstruction or of colorectal neoplasm. This rare complication remains intriguing and the possible pathogenetic mechanisms are discussed.