Types of Sun Damage: Atypical Moles

As you continue to go outside unprotected from the sun’s rays, the risk of sun damage to your skin rises. Moles, or nevi, are one of the signs of sun damage to the skin. They are composed of specialized skin cells, called melanocytes, which produce and store the dark pigment melanin. Melanocytes are responsible for imparting color to the skin; dark skin has more melanocytes and melanin than fairer skin. Some moles have clinical appearances that are quite different from the usual moles. Atypical moles are not necessarily cancerous. However, they can be considered as cancer precursors, and some eventually transform to malignant melanoma.


Atypical moles may be inherited or acquired. Inherited atypical moles are associated with mutations in several genes, as well as with familial syndromes, such as familial atypical mole and melanoma (FAMM) syndrome. FAMM is characterized by numerous atypical moles, distinct histological features and a strong family history of melanoma.

Acquired atypical moles, on the other hand, are thought to be due to ultraviolet (UV) radiation. UV-A and UV-B light are proposed to initiate transformation of normal melanocytes to atypical melanocytes that manifest as atypical moles. If you have light skin and freckles, you have the highest risk for atypical moles. Conversely, atypical moles are rare among races with darker skin, such as Africans, Asians and Middle Easterns. These moles equally affect both sexes.

If you have a strong family history of melanomas, you are more likely to have an inherited form of atypical moles. These can appear in great numbers (up to hundreds) and begin as early as childhood and puberty. You carry a very high risk of developing melanoma later on in life. Acquired atypical moles, on the other hand, are more common if you have a history of heavy sun exposure. UV-tanning devices are now classified as carcinogenic, and their frequent use before age 30 is said to increase the risk of melanoma by up to 75 percent.

Signs and Symptoms

Atypical moles may be distinguished clinically by their appearance. They are typically asymmetrical, with irregular borders. Unlike usual moles, atypical moles are usually elevated from the surrounding skin and are larger, frequently measuring 5 to 15 mm in diameter. Their color is highly variable, ranging from dark brown to flesh colored to pink. Usually, a single atypical mole demonstrates non-uniform pigmentation. Nevertheless, despite these distinct characteristics, it is unusual for an atypical mole to have all of these. Atypical moles may arise at any time and they are not constant. Over time, new lesions can arise and old lesions can change in appearance.


Upon diagnosis of an atypical mole, the doctor will perform a complete examination of the skin to look for evidence of other moles. Ideally, you should learn how to self-examine to detect new lesions and to monitor changes in existing moles. Avoid excessive sun exposure and the use of UV-emitting devices. Regularly protect yourself with sunblock having a sun protection factor (SPF) greater than 30.

While it is not possible to distinguish a noncancerous atypical mole from a cancerous melanoma based on clinical features alone, the doctor can perform a biopsy of the suspicious mole for histological confirmation.

Have specific questions?

All Article Categories

Before & After Photos

Suggested Doctors

Recently Asked Questions