Halo congenital nevus associated with extralesional vitiligo

Halo nevus is a pigmented nevus surrounded by a round or oval depigmentation. Of patients with halo nevus, 18 to 26% patients have vitiligo, either involving the nevus or at a distant site. While the exact etiology of halo formation and vitiligo is unknown, several theories suggest that common immunologic mechanisms are involved in the destruction of melanocytes of both phenomena. Unlike common melanocytic nevus, congenital nevus associated with both halo formation and concurrent extralesional vitiligo is very uncommon and only one case has been reported in the Korean dermatological literature. A 19-year-old female presented with surrounding depigmentation around a congenital hairy nevus on the left forearm. Simultaneously, vitiligo appeared on the lowerabdomen and surrounding regions of both areola. The halo depigmented lesion around congenital nevus and the periareolar vitiliginous lesion shared some histological and immunohistochemical features. These findings further support common immunological mechanisms of pigment destruction in both phenomena.