Moles (Nevi)

What Is It?

Common moles are small, pigmented spots on the skin that usually appear during childhood or adolescence, although they are sometimes present at birth. They are composed of clusters of pigmented cells called melanocytes. Moles may multiply in number during adolescence and pregnancy, and existing ones may enlarge or darken somewhat during these times. Despite such changes, moles should always remain:

• Evenly pigmented
• Sharply demarcated
• Symmetrical in shape and color

Symptoms

Moles can vary in color. They can be flesh-colored, yellow-brown or black. They also can be flat or raised and can be smooth, hairy or warty. Although moles usually do not become cancerous, a malignant melanoma can begin as a mole. For this reason, it is important to monitor moles and have them examined by a dermatologist if they:

• Enlarge suddenly
• Develop an irregular border
• Darken or become inflamed
• Show spotty color changes
• Begin to bleed, crack or itch
• Become painful

Moles called atypical moles, or dysplastic nevi, have somewhat different physical characteristics and sometimes run in families. They are more likely than common moles to turn into cancer. Simple dysplastic nevi are common, but people with multiple dysplastic nevi and melanoma in two or more first-degree relatives have 25 times the risk of developing melanoma. This is called the dysplastic nevus-melanoma syndrome.

Diagnosis

Your doctor can determine the type of mole you have by looking at it:

Common moles are generally no more than 1 to 10 millimeters (usually less than half an inch) in diameter. They are flesh-colored, yellow-brown or black and can be located anywhere on the body. They appear during childhood or adolescence.

Atypical moles (dysplastic nevi) are usually larger in diameter (5 to 12 millimeters). They are tan to dark brown with a pink background and may have a mixture of colors, including tan, brown, pink and black. The border is irregular and indistinct and often fades into the surrounding skin. Most commonly, atypical moles appear on sun-exposed skin, but they can occur elsewhere, and they continue to develop after age 35.

Expected Duration

Most moles never become a problem. However, moles should be inspected regularly for any abnormal changes.