Nevus sebaceus is a circumscribed hamartoma composed primarily of sebaceous glands. The condition affects 0.3% of newborns, with sporadic but equal frequency in males and females of all races. The lesion is usually noted as solitary hairless patch on the scalp (left image) or as a velvety tan or orange-yellow plaque in other areas (right image).
The infantile hemangiomas in PHACE syndrome are usually large and segmental, meaning that they cover a territory rather than appearing to arise from a single focal point. Most are located on the face or scalp. In the newborn period, segmental hemangiomas may have a unique "telangiectatic" appearance or may appear as faintly erythematous patches. Early recognition of these patterns is important to avoid confusing the lesions with capillary malformations or "port-wine stains."