Serial ultrasonic changes of the bladder diverticulum during urination: report of one case.

A seven-year-old boy with a retrovesical diverticulum and ipsilateral renal dysplasia is reported. He had had a history of frequent urination and dysuria for four years. According to sonography, the volume of bladder diverticulum obviously changed during urination. The diverticulum presented as a temporary large reservoir of the bladder. In this case, serial ultrasonic changes assisted understanding of the role of the diverticulum during urination.