Nevus sebaceus of Jadassohn is an organoid nevus composed of varying admixtures of sebaceous glands, hair follicles, and apocrine glands. The degree of differentiation of these appendages can be related to age. Clinically this nevus appears as a yellow, hairless plaque on the scalp or face of infants, but it may occasionally arise in adult life or in unusual locations such as the back or the inguinal or pubic regions. Cerebriform, linear, irregular, zosteriform, and multiple lesions have all been described.1,2 Development of various malignant or benign adnexal tumors often occurs with advancing age but can be seen in young adults.3
Recently, Fellner and Katz4 emphasized the occasional close clinical resemblance of pigmented basal cell carcinoma to superficial spreading melanoma. The following case of pseudomelanoma arising in a patient with nevus sebaceus is another example of the diagnostic dilemma these lesions can cause.
Report of a Case
Nagy R, Vasily DB. Pseudomelanoma in Nevus Sebaceus of Jadassohn. Arch Dermatol. 1979;115(8):1004–1005. doi:10.1001/archderm.1979.04010080062030