Leiomyomas of anorectal localization are infrequent tumors originated from vaginal smooth muscle of the rectal wall or less frequently from the rectovaginal septum. The primary management of this entity is surgical. Only a few cases have been reported in the literature and none has been reported during gestation. In this document we report the case of a 37 year old woman, with a 22 week pregnancy, who noted the presence of a rectovaginal mass compatible with a gigantic extra rectal leiomyoma of a rapidly progressive nature, associated with intense pain and bowel obstruction symptoms, which was successfully resected through a transperineal approach.