Congenital bladder diverticulum: an unusual presentation with abdominal mass, urinary retention, and renal failure in a young adult.

Computed tomographic (CT) evaluation of an abdominal mass diagnosed a huge 2-L congenital bladder diverticulum that caused urinary retention and ureteral compression leading to renal failure. The patient's renal failure resolved with decompression. His voiding dysfunction and retention resolved following diverticulectomy.