Becker's melanosis in a woman.

Becker's melanosis is a relatively common, benign hamartoma, which is usually characterized by a hyperpigmented, hypertrichotic patch on the upper trunk or proximal upper extremities of males, with its onset during the peripubertal years. Commonly, there is an associated smooth muscle hamartoma on histology. We present a woman with a Becker's melanosis on the leg without hypertrichosis. We believe that the spectrum of Becker's nevus is greater than commonly thought and that cases similar to ours are not rare, but have been diagnosed as other conditions.