Multiple familial smooth muscle hamartomas.

Smooth muscle hamartoma is a cutaneous abnormality characterized by a disorganized proliferation of normal muscle fibers of arrector pili. Usually a single congenital hypertrichotic plaque involves the trunk and the extremities. Multiple lesions have rarely been reported in the literature. We describe three members of the same family with multiple skin-colored patches on the back and legs, histologically confirmed as smooth muscle hamartomas. To our knowledge this is the first report of multiple smooth muscle hamartomas in different members of the same family and quite interestingly involving the same skin site.