A seborrhoeic keratosis is a harmless warty spot that appears during adult life as a common sign of skin aging. Some people have hundreds of them. Seborrhoeic keratosis (or seborrheic keratosis, using American spelling is also called SK, basal cell papilloma, senile wart, brown wart or barnacle.
A seborrheic keratosis usually appears as a brown, black or light tan growth on the face, chest, shoulders or back. The growth has a waxy, scaly, slightly elevated appearance. Occasionally, it appears singly, but multiple growths are more common. Seborrheic keratoses don't become cancerous, but they can look like skin cancer.