Extensive nevus comedonicus.

A 19-year-old woman had an extensive nevus comedonicus affecting the left arm, trunk, and leg. Her condition was complicated by episodes of recurrent cyst formation and secondary infection. These were reduced in extent and frequency during 14 months of treatment with a combined progesterone-estrogen contraceptive preparation, and the appearance of the lesions affecting the leg was improved. The clinical features, histogenesis, histology, and treatment of nevus comedonicus are discussed.