Moles (Nevi)

What Is It?

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. People may develop more moles during adolescence and pregnancy, and existing ones may enlarge or darken somewhat during these times. Despite such changes, moles should always remain:

  • Evenly pigmented — The color is the same across the mole.

  • Sharply demarcated — The edges of the mole are clear-cut.

  • Symmetrical in shape and color — All parts of the mole look similar.

Symptoms

Moles can vary in color. They can be flesh-colored, yellow-brown or dark brown. They also can be flat or raised and can be smooth, hairy or warty. Although moles usually are harmless, in some cases they can become cancerous, causing a potentially deadly tumor called malignant melanoma. For this reason, it is important to monitor moles and have them examined by a dermatologist if they:

To continue reading this article, you must login.
  • Research health conditions
  • Check your symptoms
  • Prepare for a doctor's visit or test
  • Find the best treatments and procedures for you
  • Explore options for better nutrition and exercise
Learn more about the many benefits and features of joining Harvard Health Online »