Back to previous menu

An atypical nevus (also called a dysplastic nevus) is a benign growth that may share some of the clinical or microscopic features of melanoma, but is not a melanoma or any other form of cancer. However, the presence of atypical nevi may increase the risk of developing a melanoma, or be a marker for someone who is at risk of developing melanoma. This increased risk varies from very small for those with a single atypical nevus to higher for those with many.

What does an atypical nevus look like?
By definition, atypical nevi can have a variable appearance. They often show ABCDE features: A. asymmetrical (one portion larger than the other), B. tend to have an irregular border which can fade imperceptibly into the surrounding skin, C. variably colored (typically with shades of tan, brown, black; and red), D. large (diameter > 6 mm), and E. slightly raised (elevated). An atypical nevus will have characteristic microscopic features found on a skin biopsy. The claim to fame of the atypical nevus is that it often can look like a melanoma.

Where do atypical nevi occur?
Atypical nevi can occur anywhere on the body, and usually begin to appear at puberty. They may however, be more common in sun-exposed areas, the back, and the legs.

What does it mean if I have a single atypical nevus?
The lifetime risk of a person in the U.S. 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. However, an atypical nevus is not the same as melanoma and does not need to be treated aggressively, but should be observed for changes, biopsied, or conservatively excised.

What does it mean if I have many moles and atypical nevi?
The risk of developing melanoma is higher if a patient with atypical nevi has a personal or family history of melanoma. When a patient has multiple atypical and normal nevi (moles) and one of their relatives has melanoma, they may have Familial Atypical Mole Syndrome.

What is Familial Atypical Mole Syndrome (FAMS)?
The National Institute of Health Consensus Conference has defined the Familial Atypical Mole syndrome as those persons meeting the following criteria: 1. A first-degree (e.g., parent, sibling or child) or second-degree (e.g., grandparent, grandchild, aunt, uncle) relative with malignant melanoma. 2. A large number of nevi, often more than 50, some of which are atypical nevi. 3. Nevi that demonstrate certain microscopic features.

What does it mean if I have Familial Atypical Mole Syndrome?
A person diagnosed with Familial Atypical Mole Syndrome is at significantly increased risk of developing melanoma. Both the number of nevi and number of family members with melanoma independently increase the risk of developing melanoma.

What should I do if my dermatologist tells me I have Familial Atypical Mole Syndrome?
Patients with FAMS should examine their own skin every two to three months. Information on the early signs of melanoma is available from your dermatologist or the American Academy of Dermatology. Patients, beginning at about puberty, should undergo a full body screen from their dermatologist every 3 to 12 months. Your dermatologist might also recommend regular ophthalmologic examination, baseline skin photographing, or even regular screening of relatives. The aim of all of these measures is to permit early detection of melanoma, should it occur. Melanoma detected at the early stages has a much higher rate of cure than do later stages of melanoma.

What can I do to prevent the development of melanoma?
Ultraviolet light avoidance is important to help prevent development of melanoma. Outdoor activity should be avoided between late morning and early afternoon, tanning parlors should be shunned, and wide brimmed hats should be worn year round along with other protective clothing. Regular use of sunscreen (SPF 15 or higher) is advised, even for a brief exposure to sunlight. Sunscreen should be reapplied every 1 1/2 hours in prolonged sun exposure. All of these precautions can be important steps to preventing melanoma in all patients.

 Back to previous menu