Pseudomelanoma following laser therapy for congenital nevus

Benign nevi can be removed by a variety of procedures including surgical excision, electrocautery, slicing off the protruding portion by a shave biopsy, cryotherapy, dermabrasion, etc. Except in the case of complete excision, these procedures may often be followed by recurrence. We describe a congenital nevus that was incompletely removed by CO2 laser therapy. When the lesion recurred, it had clinical as well as histologic features in common with malignant melanoma, although it was completely benign.