Moles are spots on the skin where pigmented cells have clustered together. They typically appear as light to dark brown spots on the skin. They can be flat or raised. Most people have benign moles, which are harmless.

Dysplastic nevi are atypical moles. They can eventually turn into a type of skin cancer called melanoma.


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Moles develop from cells in the skin called melanocytes. Normally, these cells are evenly spread out in your skin. When you have a mole, these cells have formed a cluster.

Risk Factors

Your chances of moles are higher if you have:

  • Moles that exist at birth
  • Family members with moles
  • Been exposed to a lot of sunlight—can happen with a sunburn


Most people have some benign moles that appear at birth through adolescence. Most adults have 10-40 moles.

Benign moles can appear anywhere on the body. They look:

  • Light to dark brown, but can also be yellow-brown or flesh tone
  • One color
  • Round or oval with distinct edges
  • Flat and smooth—sometimes they may become be raised, rough, or grow hair

Signs that a mole may be atypical include:

  • Sudden change in size, color, shape, texture, or how they feel
  • 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 with a 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?

Call your doctor if you:

  • Are worried because a mole doesn’t look the same as others
  • Are over 30 years old and notice a new mole
  • Notice any of your moles show signs of being atypical


The doctor will ask about your symptoms and health history. You may have a:

  • Physical exam
  • Skin exam
  • Biopsy to test the skin for a cause such as cancer


Benign moles do not need to be treated. Surgery removes unsightly or irritated moles

Care for atypical moles includes watching it for changes or removing it. Atypical moles that are cancerous or suspected of being so can be removed. The mole tissue is examined under a microscope. You may need more surgery to remove the rest of the mole and any healthy tissue around it.


To lower your chances of moles becoming atypical or 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 advised by your doctor.


American Academy of Dermatology

American Cancer Society


Canadian Dermatology Association

Health Canada


Common benign skin lesions. EBSCO DynaMed Plus website. Available at: Updated February 5, 2018. Accessed June 20, 2018.

Common moles, dysplastic nevi, and risk of melanoma. National Cancer Institute website. Available at: Updated April 27, 2018. Accessed June 20, 2018.

Dysplastic nevus. EBSCO DynaMed Plus website. Available at: Updated March 11, 2016. Accessed June 20, 2018.

Moles. American Academy of Dermatology website. Available at: Accessed June 20, 2018.

Sunscreen FAQs. American Academy of Dermatology website. Available at: Accessed June 20, 2018.

Last reviewed May 2018 by EBSCO Medical Review Board Marcie L. Sidman, MD  Last Updated: 6/20/2018