Halo congenital nevus.

A 24-year-old woman noted a depigmented halo around a pigmented lesion that had been present on her abdomen since birth. The halo and the central pigmented zone showed no change during the following year. Light and electron microscopic studies disclosed an uninflamed nevus extending to the deep reticular dermis; peripherally, the basal layer of the epidermis was depigmented. These findings indicate that a halo may develop about an uninflamed nevus that does not involute, and that the nevus may show the specific histopathology of congenital nevus.