Urethral leiomyoma in a cat.

A 13-year-old spayed cat was examined because of a suspected lower urinary tract obstruction. After 2 days, a urethral catheter could not be passed, and the cat was euthanatized. At necropsy, a 1.2-cm intramural mass was detected, obstructing the proximal portion of the urethra. Histologic examination of the well-circumscribed mass revealed a urethral leiomyoma.