Leiomyosarcoma of the dartos muscle.

Smooth muscle is seen in the skin in three locations, the arrectores pilorum muscles, the wall of vessels and the specialized muscles in genital skin (the dartos, vulvar, and mamillary muscles of the scrotum, labia majora, and the breast, respectively). We report a case of a leiomyosarcoma of the dartos muscle in a 57-year-old man. The histological features of this tumor are similar to the previously reported cases of leiomyosarcomas of the skin thought to originate in arrectores pilorum muscles and the wall of vessels.