Moles, known medically as nevi, are clusters of pigmented cells that often appear as small, dark brown spots. However, moles can come in a range of colors and can develop virtually anywhere on your body.

Most moles are harmless, but in rare cases, moles may become cancerous. Monitoring moles and other pigmented patches is an important step in detecting skin cancer, especially malignant melanoma. Not all melanomas develop from pre-existing moles, however. Some moles may begin as a new growth on the skin.

Dec. 06, 2011