"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.