Perianal striated muscle hamartoma associated with hemangioma.

Striated muscle hamartoma is a rare entity which was described only recently. It is a congenital malformation characterized by the presence of striated, mature muscle fibers in the reticular dermis and hypodermis. We describe a striated muscle hamartoma of the perianal region in a female infant associated with an hemangioma in the same area that regressed completely. Including the present patient, only 14 cases of striated muscle hamartomas have been reported, but this association with an hemangioma is unique. The lesion was polypoid and histopathologic examination showed numerous striated muscle fibers located within the dermis.