Malignant melanoma arising in a sebaceous nevus of the scalp.

This is the first report of malignant melanoma arising from sebaceous nevus (SN) of the scalp, although it has been known that various benign and malignant neoplasms may develop in association with SN. After the excisional biopsy for SN with 5 mm free margin, pathological examination revealed the coexistence of nodular melanoma invading to the reticular dermis (IV level of Clark) for a maximal depth of 4 mm. After resection with another 20 mm free margin, there has been no evidence of local recurrence or distant metastasis for nine years.