[Urinary retention caused by female urethral diverticulum]

We report a 49-year-old female who had circumferential urethral diverticulum. She was admitted to our department for urinary retention. A cystic lesion surrounding the urethra had been detected by magnetic resonance imaging. We diagnosed the lesion as a urethral diverticulum after injecting dye to the cystic mass from vagina and confirming its discharge from the urethra at the pubic side by urethroscopy. Transvaginal resection of the diverticulum was peformed. In general, 4% of female urethral diverticula cause urinary retention. On the other hand, 1% of female bladder outlet obstruction is caused by urethral diverticula. It is neccessary for us to keep in mind urethral diverticulum when we evaluate female patients with urinary retention.