Atypical  moles (also known as dysplastic nevi) do not look like ordinary moles. They may have some or all of the following characteristics:

• Larger than average (5mm-15mm)
• Irregular or indistinct borders
• Color is variable throughout and may be pink, brown and /or black
• Surface may be bumpy or smooth
• May resemble a fried egg, with a raised center of darker pigmentation surrounded by a flat, lighter area

Atypical moles may appear anywhere on the body but are most commonly found on the back, chest, buttocks, and scalp. They are more common in areas that have been exposed to the sun. Fair-skinned people with light colored hair and/or freckles are most at risk of getting atypical nevi, especially if they have been frequently in the sun. 

 Risk 

• Individuals with dysplastic nevi and no personal or family history of melanoma have a 7 to 27 times greater risk of developing melanoma.
• The risk of melanoma increases significantly if there is a personal or family history of melanoma 

Dysplastic Nevi Syndrome

• Dysplastic nevus syndrome (DNS), also called atypical nevus syndrome (ANS), is when a person develops many more moles than the general population. These syndromes may be acquired or inherited. In the acquired population, there is no family history. In the inherited syndrome, a person comes from a family where others have had this condition. 

The condition is defined as:

• Having greater than 50 moles
• At least some of the moles have atypical features, such as irregular borders, colors, etc.
• Having less than 50 moles but at least 5 atypical moles

Risks

• People with acquired DNS , who do not have a family history of melanoma, have an increased risk of developing melanoma
• People with inherited DNS, and a family history of melanoma, defined as having two or more first degree relatives (parent, sibling or child) have FAMM (Familial Multiple Mole and Melanoma)
• People with FAMM have a very high risk of melanoma, up to 100% by age 80

Treatment 

When pathologists or dermatopathologists see an atypical mole, they will often rate the degree of atypica as mild, moderate or severe.

• There are no specific guidelines for what should be done to a mole based on the degree of atypia
• Because the vast majority of atypical nevi do not turn into melanoma, it is not the standard of care to just remove all of them
• Nearly all dermatologists will remove any severe atypical mole (usually with an extra area of normal skin to make certain it is completely removed)
• Many dermatologists will re-excise (cut) moderately dysplastic moles, while other dermatologists feel that mildly atypical moles do not need to be cut out and wil instead opt to watch them
• Close monitoring is very important, and people diagnosed with atypical nevi should self-examine their skin for new moles or for changes in existing moles

For more on skin self-examination, click here