Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Melanoma/Skin Cancer Health Center

Font Size

Atypical Moles

The skin cells that produce pigment (melanocytes) sometimes group together to form moles. Most people have at least 10 moles on their bodies.

Melanocytes can form abnormal moles, also called atypical moles or dysplastic nevi. These moles are not malignant themselves. But their presence is a warning of an inherited tendency to develop melanoma. Some people have only 1 or 2 atypical moles. Some people may have more than 100. The tendency to develop atypical moles can run in families (inherited predisposition).

Early signs of melanoma in atypical moles

The ABCDE rule camera.gif of detection means watching for:

  • AsymmetryAsymmetry camera.gif. One half doesn't match the other half.
  • Border irregularityBorder irregularity camera.gif. The edges are ragged, notched, or blurred.
  • ColorColor camera.gif. The pigmentation is not uniform. Shades of tan, brown, and black are present. Dashes of red, white, and blue add to the mottled appearance. Changes in color distribution, especially the spread of color from the edge of a mole into the surrounding skin, also are an indicator of early melanoma.
  • DiameterDiameter camera.gif. The size of the mole is larger than 1/4 inch (6 mm), or about the size of a pencil eraser. Any growth of a mole should be of concern.
  • EvolutionEvolution camera.gif. There is a change in the size, shape, symptoms (such as itching or tenderness), surface (especially bleeding), or color of a mole.

Atypical moles are seen most commonly on the back but may be anywhere on the body, including below the waist, on the scalp, or on the breasts or buttocks. They may fade into surrounding skin and include a flat portion that is level with the skin surface. They may be smooth, slightly scaly, or have a rough, irregular, "pebbly" appearance.

Atypical moles usually are not present at birth but develop some time later.

Several types of atypical moles are known to develop before melanoma (melanoma precursors). Atypical moles are the most common precursor, but not all atypical moles develop into melanoma. Precursors to melanoma include:

  • Giant congenital melanocytic nevus (giant hairy nevus or garment nevus).
  • Small to medium-sized congenital melanocytic nevus.
  • Some heavily pigmented lesions of the membrane that line the eyelids (conjunctiva).

ByHealthwise Staff
Primary Medical ReviewerKathleen Romito, MD - Family Medicine
Specialist Medical ReviewerAmy McMichael, MD - Dermatology

Current as ofNovember 14, 2014

WebMD Medical Reference from Healthwise

Last Updated: November 14, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Today on WebMD

Malignant melanoma
About 40-50 percent of those who live to be 65 may get it. Here’s how to spot early.
Woman checking out tan lines
There’s a dark side to that strive for beauty. See them here.
sauteed cherry tomatoes
Fight cancer one plate at a time.
Lung cancer xray
See it in pictures, plus read the facts.
12 Ways to Protect Your Skin from Melanoma
precancerous lesions slideshow
Do You Know Your Melanoma ABCs
15 Cancer Symptoms Men Ignore
screening tests for men
Vitamin D
Is That Mole Skin Cancer
Brilliant sun rays