A number of benign cutaneous neoplasms have been reported in association with nevus sebaceus. The most commonly encountered are trichoblastoma-like lesions and syringocystadenoma papilliferum. The image shows a benign adnexal tumor in the setting of a nevus sebaceus. Note the hyperplastic sebaceous glands at the base of the tumor. Uncommonly, one sees malignant neoplasms arising within the context of a nevus sebaceus, including basal cell carcinoma, squamous cell carcinoma, melanoma, sebaceous carcinoma, eccrine porocarcinoma and others.