Background: Melanocytic nevi, particularly dysplastic nevi (DN), are important markers of increased risk of malignant melanoma in adults, but little is known about their prevalence and relation to melanoma in children.
Objective: Our purpose was to define the prevalence of DN, number of nevi, and their relation to the risk of melanoma in children younger than 20 years of age from melanoma-prone families.
Methods: One hundred twenty-five persons younger than 20 years of age, from 23 melanoma-prone families, underwent clinical evaluation with nevus counts, photography, and biopsy of suspected melanocytic lesions and were observed for development of DN and melanoma.
Results: In melanoma-prone families, 37% of children had DN. The patients were divided into four categories: those with melanoma, DN (without melanoma), indeterminant (largely because of age at examination), and unaffected. The risk of melanoma was assessed by nevus number and presence of DN. High nevus number was strongly correlated with the presence of DN. The risk of the development of melanoma in children from melanoma-prone families appeared most related to the presence of DN (relative risk, 45; 95% confidence intervals, 2.6-786.4) and started at an early age. Of note, all children in whom melanoma developed had DN.
Conclusion: Family history of melanoma and the presence of DN defines children with a high risk for melanoma developing at an early age.