In adults, rectal leiomyosarcoma is uncommon, and anal leiomyosarcoma
is even more rare. We report one patient with anal leiomyosarcoma and
one patient with a biphasic clinical history, with three occurrences o
f perineal leiomyosarcomas after surgically resected rectal leiomyoma.
We discuss the characteristics of these rare entities based upon a re
view of the literature.