Leiomyosarcoma of the anal canal: a case report

Leiomyosarcoma (LMS) of the colon, rectum, and anus comprise less than 0.1% of all rectal malignancies with isolated leiomyosarcomas of the anal canal representing only eight reported cases. We report one more case and a review of the world literature.

An 80-year-old male presented with a complaint of bright red blood per rectum, constipation, and a subjective history of a rectal mass diagnosed 3 years prior. Pertinent findings on physical exam included a hard, non-mobile mass in the anus which biopsy showed to be a LMS. The patient only wished to have a local excision of the mass performed. At the time of operation the perianal mass extended from the external sphincters into the anal canal. The mass was excised with clean margins. The patient refused adjuvant therapy. Approximately 7 months later, the patient was found to have a local recurrence. At this time the patient opted for local excision and radiotherapy.

Isolated LMS of the anus is an extremely rare finding with only eight previous reports in the world literature. LMS is an aggressive tumor with a high local recurrence rate as well as significant hematogenous spread. Due to its rarity, there is insufficient data regarding the optimal treatment. Our literature review has displayed some limited preference for radical surgery over local excision, which may in turn lead to a better outcome.