Phenotypic and Dermoscopic Features in First-Degree Relatives of Melanoma Patients: A Controlled Cross-Sectional Study.

BACKGROUND

Melanoma is a multifactorial malignancy influenced by genetic susceptibility, phenotypic traits, and exposure to ultraviolet radiation. First-degree relatives of melanoma patients represent a recognized high-risk group, yet data integrating detailed dermoscopic assessment with clinical risk profiling remain limited. This study aimed to compare phenotypic characteristics, nevus patterns, and sun-exposure-related factors between first-degree relatives of melanoma patients and matched controls, and to evaluate whether observed associations reflect an independent familial risk pattern.

METHODS

In this controlled cross-sectional study, 100 first-degree relatives of 68 melanoma patients and 102 geographically matched controls without a personal or family history of melanoma underwent full-body dermatologic and dermoscopic examination. Nevi were classified by number, type, and anatomical distribution. Demographic, phenotypic, and behavioral variables were recorded. To address potential within-family correlation, a sensitivity analysis was conducted by randomly selecting one relative per family. Multivariable logistic regression adjusted for age and sex.

RESULTS

First-degree relatives demonstrated a significantly higher prevalence of individuals with >50 nevi and atypical nevi compared with controls. They also reported an earlier age at first sunburn and showed distinct phenotypic characteristics, including lighter hair color. In sensitivity analyses including one relative per family, these associations remained significant. After adjustment for age and sex, familial status remained independently associated with a high nevus count and the presence of atypical nevi.

CONCLUSION

First-degree relatives of melanoma patients exhibit dermoscopic and phenotypic features consistent with an increased melanoma risk, independent of demographic differences. These findings support targeted dermoscopic surveillance and preventive education in this high-risk population to facilitate earlier detection and improved clinical outcomes.