“Clark/dysplastic” nevi with florid fibroplasia associated with pseudomelanomatous features

Background Melanocytic nevi may exhibit histologic features in common with cutaneous melanoma, creating diagnostic difficulties. Objective We sought to assess the clinical behavior of melanocytic nevi with pseudomelanomatous features in association with dermal fibrosis. Methods Forty-two melanocytic nevi with pronounced fibrosis and associated pseudomelanomatous changes were collected and studied clinically and histologically. Results The fibrosis was centrally located and laminated in appearance. It imparted a trizonal appearance: a junctional component with prominent single cells and/or irregular nests, underlying fibrosis, and a mature dermal component. No recurrence or metastases were evident over an average follow-up period of 2 years. Limitations The follow-up period was short. Conclusions The central location and laminated appearance of the fibrosis suggest that this may represent the extreme end of a spectrum of fibroplastic changes in “Clark/dysplastic” nevi. Adjacent features of “Clark/dysplastic” nevi and limitation of pseudomelanomatous features to the perifibrotic focus are important in accurately identifying these lesions. Although melanocytic nevi with exaggerated fibroplasia may show foci with melanoma-like features, they do not appear to exhibit aggressive clinical behavior.