A neonate is noted to have a soft, yellowish-colored plaque on the temple. The pregnancy was uneventful and Apgar scores at delivery were satisfactory.
Key point: This is a classic appearing nevus sebaceous (NS), a congenital hamartoma composed of both ectodermal and mesodermal structures typically affecting the scalp or face. This lesion appears in about 0.3% of all neonates. At puberty and throughout adulthood, the lesion is expected to become increasingly more verrucous.
Treatment: If a NS is excised, it is generally done for cosmetic reasons. Small lesions can be excised with primary closure.
Note: Secondary benign and malignant neoplasms arise within the adult-aged NS in about 15% of cases. These include: syringocystadenoma papilliferum (most commonly), and basal cell carcinoma (2% of NS lesions).