Pedunculated atypical cellular blue nevus.

Atypical variants of cellular blue nevus are considered to have features intermediate between typical cellular blue nevus and rare malignant blue nevus; they usually show bizarre pleomorphic cells which have prominent nucleoli. We describe a 37-year-old-Korean woman who had had an asymptomatic pedunculated single mass on her right thigh for 17 years. A skin biopsy showed a tumor consisting of intensely pigmented dendritic cells and less or nonpigmented epitheloid cells in the dermis with striking atypia. There has been no evidence of recurrence for 3 years after surgery. The diagnosis of atypical cellular blue nevus was made on the basis of clinical features and skin biopsy findings.