A mole (nevus) is a pigmented (colored) spot on the outer layer of the skin (epidermis)and can be round, oval, flat, or raised. Moles can occur singly or in clusters on any part of the body. Most moles are brown, but colors can range from pinkish flesh tones to yellow, dark blue, or black.

Everyone has at least a few moles. They generally appear by the time a person is 20 and look, at first, like freckles. A mole's color and shape don't usually change. Changes in hormone levels that occur during puberty and pregnancy can make moles larger and darker. New moles may also appear during this period.

A mole usually lasts about 50 years before beginning to fade. Some moles disappear completely, and some never lighten at all. Some moles develop stalks that raise them above the skin's surface; these moles eventually drop off.

About 1-3% of...