Health Information

Moles

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(Nevi)

Definition

Moles are spots on the skin where pigmented cells have clustered together. They typically appear as light to dark brown spots on the skin that are either flat or raised. Most people have benign moles, which are harmless.
Moles that become atypical are called dysplastic nevi. They may eventually become melanoma. Melanoma is a form of skin cancer.
Mole
mole
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Causes

Moles develop from pigment-producing cells in the skin called melanocytes. Normally, these cells are evenly distributed in your skin. When you have a mole, these cells have formed a cluster.

Risk Factors

These factors increase your chance of developing moles:
  • Moles that are present at birth increase the likelihood of more moles later in life
  • Family members with moles
  • Excessive exposure to sunlight, especially sunburn

Symptoms

Most people have some benign moles that appear at birth, childhood, or adolescence. Most adults have 10-40 moles.
Benign moles, which can appear anywhere on the body, are usually:
  • Dark brown, but can also be yellow-brown or flesh tone
  • One color
  • Round or oval with distinct edges
  • Flat and smooth, but may occasionally become raised, rough, or grow hair
Signs that a mole may be atypical include:
  • Sudden change in size, color, shape, texture, or sensation
  • Large size—¼ inch or more across, about the size of an eraser at the end of a pencil
  • A mixture of colors, often including black
  • Irregular edges
  • Abnormal surface that is:
    • Scaling
    • Flaking
    • Oozing
    • Bleeding
    • Open with a sore that will not heal
    • Hard and raised lump
  • Itchy, tender, or painful
  • Abnormally colored skin around it
Irregular Border on Mole
Skin Cancer Sign: Irregular Border on Mole
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When Should I Call My Doctor?

If you are concerned about a mole because it looks different from the others, or you are over age 30 and notice a new mole, call your doctor. Also, call your doctor if you notice any signs that an existing mole may be atypical.

Diagnosis

The doctor will examine your skin and ask about your symptoms and medical history.
Your bodily tissues may be tested. This can be done with a biopsy to remove all or part of the mole to be tested for cancer cells.

Treatment

Benign moles do not need to be treated. However, surgery may be done to remove those that are unsightly or irritated.
Treatment for atypical moles include monitoring or removal. Atypical moles that are cancerous or suspected of being cancerous can be removed. The mole tissue is examined under a microscope. If cancer cells are found, more surgery is done to remove any remaining portion of the mole and surrounding tissue.

Prevention

To help prevent benign moles from becoming atypical and possibly cancerous:
To detect atypical or cancerous moles early:
  • Monitor your moles, especially atypical ones.
  • Report any changes in a mole to your doctor.
  • Have your doctor check and monitor atypical moles on a regular basis. Have moles checked more often if you have:
    • A large number of moles
    • A family or personal history of atypical moles or melanoma
Have moles removed if your doctor recommends it.

RESOURCES

American Academy of Dermatology http://www.aad.org

American Cancer Society http://www.cancer.org

CANADIAN RESOURCES

Canadian Dermatology Association http://www.dermatology.ca

Dermatologists.ca http://www.dermatologists.ca

References

Moles. American Academy of Dermatology website. Available at: http://www.aad.org/dermatology-a-to-z/diseases-and-treatments/m---p/moles. Accessed June 7, 2013.

Common Moles, Dysplastic Nevi, and Risk of Melanoma. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/cancertopics/factsheet/Risk/moles. Updated November 2011. Accessed June 7, 2013.

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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