Nevi, Atypical

Key Features

• The term "atypical nevus" or "atypical mole" has supplanted "dysplastic nevus"

• It is estimated that 5–10% of the white population in the United States has 1 or more atypical nevi

• Recreational sun exposure is a primary risk in nonfamilial cases

• There is an increased risk of melanoma in the following populations

  • Patients with 50 or more nevi with 1 or more atypical moles and 1 mole ≥ 8 mm

  • Patients with a few to many definitely atypical moles; these patients should be educated to recognize changes and be monitored every 6–12 months

  • Kindreds with familial melanoma (numerous atypical nevi and a family history of two first-degree relatives with melanoma) require closer attention because their risk of developing single or multiple melanomas approaches 50% by age 50

Clinical Findings

• The moles are large (> 6 mm in diameter), with an ill-defined, irregular border and irregularly distributed pigmentation

Diagnosis

• The diagnosis is made clinically and not histologically

Treatment

• Moles should be removed only if they are suspected to be melanomas