Leiomyosarcoma of the anal canal: case report and review of the literature.

A rare case of a leiomyosarcoma of the anal canal is presented. A 68-year-old male presented with painful defecation and rectal bleeding. Endorectal ultrasound revealed a mass invading both sphincters (T4 lesion), and extending 6 cm into the anal canal. Colonoscopy revealed an ulcerated area in the anal canal, of which biopsies revealed high-grade leiomyosarcoma--only the eighteenth such case at the time of this submission. The details of the case and teaching images are presented in detail, as is a comprehensive review of the relevant literature.