Abstract

A case of cellular blue nevus is reported. The patient is a 12-year-old Japanese girl. When she was born her mother noticed a blue spot on her buttock of the right side. Since the mother considered the spot as a mongolian spot, the patient had not been consulted any doctors until the patient noticed a subcutaneous nodule at the center of the lesion. Pathological diagnosis was cellular blue nevus. Epidermal melanocytes were intact. Although the nuclei of the dermal melanocytes were large, no atypical mitosis was found. Necrotic foci were not seen. Thus we diagnosed the lesion benign.