Megacystis secondary to congenital urethral stricture.

Functional bladder capacity at a certain age can be accurately estimated and expressed as a function of age. We present a 13-year-old boy with abdominal distention who was presumed to have ascites. Abdominal ultrasound revealed that the bladder was severely distended, and cystoscopy showed a short stricture in the bulbar urethra followed by a large bladder without obvious borders. Under general anesthesia, bladder capacity was 9250 cc. Reduction cystoplasty was performed. At the 2-year follow-up, he voided spontaneously with 20 cc post-void residual urine.