Nevus sebaceus of Jadassohn. Atypical location and associated syndromes

Benign hamartoma that can appear from birth. It is located mainly on the scalp and face; It causes an alopecic, yellowish plaque with a rough surface. It has three stages, one of epidermal hyperplasia, then a pubertal stage with development of sebaceous glands, and a late stage with development of benign or malignant tumors, especially papillary syringocystadenoma and trichoblastoma. It can appear associated with genetic syndromes. Its surgical excision is controversial.