Atypical Nevus

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Atypical Nevus pamphletAn atypical nevus or dysplastic nevus (mole) is a benign growth that may share some of the features of a melanoma, but is NOT a melanoma or any other form of cancer. The presence of an atypical nevus, however, may increase the risk of developing a melanoma, or be a marker for it. A single atypical nevus may indicate a small risk; this risk increases with the number of atypical nevi present.

What does an atypical nevus look like?

An atypical nevus can vary in appearance. Since it has the ABCDE features of a melanoma, it is important to have a dermatologist examine all moles.

AsymmetryA stands for ASYMMETRY; one half unlike the other half.
BorderB stands for BORDER; irregular, scalloped or poorly defined border.
ColorC stands for COLOR; varied from one area to another; shades of tan and brown, black; sometimes white, red or blue.
DiameterD stands for DIAMETER; while melanomas are usually greater than 6mm (the size of a pencil eraser) when diagnosed, they can be smaller.
Evolving moleExample of an evolving mole

E stands for EVOLVING; a mole or skin lesion that looks different from the rest or is changing in size, shape, or color.

Atypical Nevus

Atypical Nevus

What are the risks of atypical nevi?

The lifetime risk of a person in the United States developing melanoma is 1 in 75. A patient with one to four atypical nevi without a personal or family history of melanoma is at a slightly higher risk than the general population. The risk of developing melanoma is higher if a patient with atypical nevi has a personal or family history of melanoma. A patient who has multiple atypical and normal nevi (moles) may have Familial Atypical Nevus Syndrome, and is at an increased risk for developing a melanoma, especially if a relative had melanoma.

Where and when do atypical nevi occur?

Atypical nevi begin to appear at puberty and can occur anywhere on the body, but are more common in sun-exposed areas, the back, and the legs.

Atypical Nevus

Atypical Nevus

Treatment

Since an atypical nevus is not the same as a melanoma, it does not need to be treated aggressively but should be observed for changes, biopsied, or conservatively excised.

Familial Atypical Nevus Syndrome

The National Institute of Health Consensus Conference defines the Familial Atypical Nevus Syndrome as those persons meeting the following criteria:

  • A first-degree (e.g., parent, sibling or child) or second-degree (e.g., grandparent, grandchild, aunt, uncle) relative with malignant melanoma.
  • A large number of nevi, often more than 50, some of which are atypical nevi.
  • Nevi that demonstrate certain microscopic features.

Management of Familial Atypical Nevus Syndroms

It is important for people with Familial Atypical Nevus Syndrome to have a full body screening from a dermatologist every three to twelve months beginning with the onset of puberty. The dermatologist might also recommend regular ophthalmologic examinations, baseline skin photography, or regular screenings of relatives to permit early detection and treatment of melanoma since detection in the early stages has a much higher cure rate.

People with Familial Atypical Nevus Syndrome should also examine their own skin every month. When performing self-examinations, be aware of any lesions that appear to change in size, color, and/or shape. If a change has occurred, bring this to the attention of a dermatologist immediately. Information on the early signs of melanoma is available from the dermatologist or the American Academy of Dermatology.

Prevention of Melanoma

  • Apply a broad-spectrum sunscreen which protects against ultraviolet light (UVA and UVB) and has an SPF of 30 or higher daily.
  • Reapply approximately every two hours during prolonged sun exposure.
  • Seek shade whenever possible, especially during peak sun hours between 10 a.m. and 4 p.m.
  • Never use a tanning bed, booth, or artificial tanning devices.
  • Wear a wide-brimmed hat, sunglasses, and other protective clothing like long-sleeved shirts and pants when outdoors.

To learn more about atypical nevus, call toll-free (888) 462-DERM (3376) to find a dermatologist in your area.

AAD Web site: www.aad.org
Toll-free: (888) 462-DERM (3376)
Images used with permission of the American Academy of Dermatology
National Library of Dermatologic Teaching Slides
© 2005 American Academy of Dermatology
Revised 2001, 2005
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