Nevus sebaceous is a congenital, hairless plaque that typically occurs on the face or scalp. Such nevi are present at birth, affecting males and females of all races equally. The condition is named for an overgrowth of sebaceous gland

Sebaceous gland

The sebaceous glands are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals...

s in the area of the nevus.

Sebaceous nevi can give rise to sebaceous carcinoma. However, the rate of such malignancies is now known to be less than was previously estimated. For this reason, excision is no longer automatically recommended.