Atypical Nevus

Atypical nevi, also known as atypical moles, are benign (non-cancerous) lesions that look different from common moles. Most atypical nevi remain stable over time. However, they may increase your risk for melanoma, a serious skin cancer.


Atypical nevi can be found anywhere on the body, though you’ll usually find them in sun-exposed areas such as the back, chest, abdomen, and extremities. Their appearance meets one or more of the ABCDE guidelines of melanoma, which include:

  • Asymmetry
  • Border irregularity
  • Color variability
  • Diameter of 6mm or more
  • Evolution or change
  • Appearance different from other moles

Atypical nevi generally first appear during adolescence, although they can develop during any period of your life. They are composed of melanocytes (cells that make the pigment in your skin) that grow in organized clusters instead of being evenly distributed throughout your skin.

Learn how to examine your skin

Risk factors of atypical nevus

If you have numerous moles or a family history of moles or melanoma, you may have a higher risk of developing atypical moles or melanoma. Other contributing factors include overexposure to the sun’s ultraviolet rays, and hormonal changes during puberty and pregnancy.

Potential consequences

People with atypical nevi may be at increased risk of developing melanoma, the deadliest form of skin cancer. That means it is especially important to perform regular self-skin checks and to be familiar with the ABCDEs of melanoma.
An estimated 1 out of every 10 Americans has at least one atypical mole.
Source: American Osteopathic College of Dermatology

Treatment options for atypical nevus

Atypical nevi can be difficult to distinguish from melanoma. Your dermatologist will make a diagnosis based on the appearance of the pigmented lesion, your family history, and genetic traits. Treatment options include monitoring you closely or performing a skin biopsy.

If your dermatologist has you monitor your atypical nevi, it is likely because the visual features are not atypical enough to warrant biopsy. During your initial visit, they can keep track of questionable nevi by taking measurements, mapping the location on a body map, or taking digital photographs. Your doctor can then use these records to screen for any changes in the appearance at a follow-up visit. Should any changes occur, you will most likely need a skin biopsy.

If your dermatologist performs a skin biopsy, the procedure may be a shave biopsy, punch biopsy, or excisional biopsy. All aim to remove the entire pigmented lesion so that it may be examined under the microscope to determine the severity of the nevus and to rule out the possibility of melanoma.

Preventing atypical nevus

To protect yourself from atypical nevi, the most important prevention measure you can take is to avoid overexposure to sunlight.

You should also inspect your entire body regularly for any skin changes, and routinely visit your physician for a skin examination.

Learn more about recommended prevention and protection techniques from Spot the Spot.

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Atypical nevus resources


Review information on atypical nevi or other skin disorders with your dermatologist. Download or print these brochures and bring them to your next appointment.

Open AN brochure Open skin disorders brochure
People with 10 or more atypical moles have 12 times the risk of melanoma.
Source: Skin Cancer Foundation

Other types of skin cancer

  • Also known as solar keratosis, AK is a precancerous lesion of the outer layer of skin.
  • This is the most common form of skin cancer and usually occurs on sun-exposed areas of the body.
  • This serious form of skin cancer affects the cells that produce melanin.
  • This major cancer arises from the outer layer of the skin and mucous membranes.
  • This common, non-cancerous lesion grows on the outer layer of the skin.