Nevus sebaceus or sebaceous nevus (the first term is its Latin name, the second term is its name in English; also known as an "organoid nevus"[1]: 661  and "nevus sebaceus of Jadassohn"[2]: 773 ) is a congenital, hairless plaque that typically occurs on the face or scalp.

[3] Such nevi are classified as epidermal nevi and can be present at birth, or early childhood, and affect males and females of all races equally.

[4] The condition is named for an overgrowth of sebaceous glands, a relatively uncommon hamartoma, in the area of the nevus.

[5] Skin growths such as benign tumors and basal cell carcinoma can arise in sebaceous nevi, usually after puberty.

For this reason, excision is no longer automatically recommended.