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Melanocytic nevi in childhood indicated melanoma risk in adulthood

The number and distribution of melanocytic nevi in childhood among patients with familial melanoma were major risk factors for children developing melanoma as adults, according to recent study results.

One hundred thirty-three children (mean age, 13 years; 60.9% male; mean nevi count, 36) from 34 families diagnosed with familial melanoma were photographed between 1985 and 1990 at Leiden University Medical Center in the Netherlands. Researchers collected more than 20 years of follow-up data, including gene-carrier status, melanoma diagnoses and nevi excisions. All patients among the original study were invited for a second visit approximately 20 years later.

Forty patients, now adults (mean age, 34 years), were included in a second nevi count (mean nevi, 39) in which childhood phenotypic data were compared with adulthood nevus numbers (mean nevi, 121). Associations were determined through survival and correlation analyses and t tests. Melanoma occurrence and mutation carrier status were correlated with nevus count and distribution in childhood as main outcomes.

Of the original patients, 15 (11.3%) had developed at least one melanoma or melanoma in situ; seven patients had more than one melanoma. Mean age for developing first melanoma was 26 years; one person, aged 38 years, died of melanoma.

Total number of atypical nevi in childhood (HR=1.21; 95% CI, 1.02-1.44), atypical nevi count on the buttocks (HR=14; 95% CI, 2.94-66.55) and number of excisions during follow-up (HR=1.27; 95% CI, 1.23-1.31) were significant risks for melanoma.

Distribution of nevi in childhood and adulthood was correlated to the distribution of melanomas (0.89; 95% CI, 0.67-0.96 and 0.99; 95% CI, 0.98-1, respectively).

Based on study data, “physicians should take additional care of children from families at high risk of melanoma,” the researchers concluded. “Children with a high number of melanocytic nevi and children with atypical nevi should be included in a surveillance program with their parents.”

Disclosure: The researchers report no relevant financial disclosures.