Pigmented spindle cell nevus. Clinical and histologic review of 90 cases.

A clinical and histologic review of 90 patients with melanocytic lesions termed pigmented spindle cell nevi (PSCN) is reported. The lesions are small in surface diameter, sharply confined both clinically and histologically, and often occur on the proximal extremities of young adults. They are generally of recent onset, moderately to heavily pigmented, and made up of nests of spindled cells confined to the epidermis and papillary dermis. There were 30 male and 60 female patients. Their average age was 25.3 years (ranging from 2.5 to 56 years). Lesions were located on the extremities in 61 cases (67%). Follow-up was possible in 38 cases seen more than 6 months after histologic diagnosis and ranged up to 40 months (average 14 months). No local recurrence or distant spread was found. The importance of recognizing this lesion lies in differentiating it from malignant melanoma. Conservative but complete excision has resulted in no recorded instances of local recurrence or distant spread.