Cellular blue nevus of the scalp infiltrating the underlying bone: case report and review.

Cellular blue nevi (CBN) are benign tumors of the skin derived from dermal melanocytes histologically characterized by increased cellularity and often by a dual cell population of nevoid cells. CBN rarely tend to invade the underlying tissues. Only six cases of CBN of the scalp invading the skull have been reported. A new case of a CBN infiltrating the underlying bone is presented. The patient, a 23-year-old woman, had a large hairless area on her right parietal scalp, present since the early months of life. Her past medical history included, on the same site, the presence, at birth, of a raised, dark, soft and hairless mass that was subsequently electrodesiccated. Radiographs of the skull showed an area of osteolysis underlying the cutaneous lesion. Histologic examination of a biopsy specimen revealed a CBN of the scalp infiltrating the underlying bone. Surgical resection of the entire lesion was planned. There were no other anomalies or malignancies. The patient is currently being followed in our clinic.