Ureteric obstruction due to sigmoid diverticulitis.

Two cases in which the ureter was obstructed by an inflammatory diverticular mass are presented. The difficulties of distinguishing such a mass from a carcinoma both clinically and at operation are emphasized. In order to minimize the risk of ureteric injury and to facilitate planning of the operative procedure, it is recommended that intravenous pyelography should be performed before resection of a suspected diverticular mass.