Keratoacanthoma Arising in a Linear Epidermal Nevus

To our knowledge, keratoacanthoma has not been reported to develop within a linear epidermal nevus. We describe herein a patient with the simultaneous development of two keratoacanthomas in a linear epidermal nevus. REPORT OF A CASE A 26-year-old woman was referred to the University of Virginia Dermatology Clinic, Charlottesville, for evaluation of two asymptomatic nodules that had developed within a "birthmark" on her right arm. The lesions had appeared suddenly, one month earlier, and had continued to enlarge since that time. There was no history of preceding trauma.On physical examination, the patient had a zosteriform epidermal nevus that extended proximally from the distal aspect of her right thumb to her right shoulder (Fig 1). There were two dome-shaped nodules, each 1 cm in diameter, located within the nevus. One was located on the dorsal aspect of the wrist and the other was immediately proximal to the elbow (Fig 1).