Image of a slate gray nevus birthmark
Previous Next 4 of 7 Slate gray nevus

A slate gray nevus is a usually harmless, large, blue-gray birthmark. It can be mistaken for a bruise. This type of birthmark is more common in black children and those of Asian descent. It usually appears on the lower back and, less commonly, on the buttocks, legs or arms. A slate gray nevus tends to fade during childhood and requires no treatment. It's also known as a dermal melanocytosis or a Mongolian spot.