Atypical Junctional Melanocytic Hyperplasia with Intradermal Nevus

Jeon, Su Young; Ha, Seung Min; Ko, Dong Yeob; Song, Ki Hoon; Kim, Ki Ho

Abstract

Atypical junctional melanocytic hyperplasia is a rare condition with unknown etiology. It is characterized by focal atypical melanocytic proliferation limited in the basal layer. Although this lesion is difficult to separate from melanoma in situ (MIS), it could be distinguished from MIS by the lack of several features, including lateral spread, upward epidermal migration, marked cytologic atypia, finely granular "smoky" melanin pigment, mitotic figures, and a subjacent host inflammatory response. In one study, atypical junctional melanocytic hyperplasia was found in 6.2% (25/400) of otherwise normal intradermal nevi. However, to our knowledge, no case of atypical junctional melanocytic hyperplasia with intradermal nevus has ever been published in Korean dermatologic literatures. Herein, we report a rare and interesting case of atypical junctional melanocytic hyperplasia with intradermal nevus.