Melanocytic nevi of the auricular region: histologic characteristics and diagnostic difficulties

We examined auricular melanocytic nevi to evaluate their architectural and cytologic features. A retrospective analysis of 21 auricular melanocytic nevi was conducted during 3 years. The nevi were evaluated for cytologic atypia, architectural disorder, location of epidermal nests, pagetoid spread, growth pattern (symmetry versus asymmetry), demarcation of lateral borders, and host response (lymphocytic infiltrate and/or lamellar fibroplasia). Eleven cases (52.4%) measured at least 6 mm in greatest dimension and 6 cases (28.6%) were asymmetric. Fourteen cases (66.7%) were ill demarcated. Pagetoid spread was present in 12 cases (57.1%). Ten cases (47.6%) showed moderate to severe cytologic atypia. Nucleoli were prominent in 9 cases (42.8%). None of the cases showed mitoses or apoptotic melanocytes. Auricular melanocytic nevi, like those occurring in the acral, flexural, and genital areas, may exhibit some histologic features commonly found in melanomas. Careful histologic interpretation of these lesions is recommended.