Sex Differences in Nevus Count, Size, and Distribution: Insights From Automated 3D Total Body Surface Imaging

ABSTRACT Background Sex‐based differences in melanocytic nevus patterns are recognized, yet their phenotypic characteristics across the body remain incompletely understood, especially in individuals at high risk for melanoma. Advances in imaging technology, such as 3D total body imaging, enable more accurate and comprehensive nevus assessment. Objectives This study aimed to investigate sex‐based differences in nevus phenotype using automated 3D total body imaging in a high‐risk melanoma population. Methods A total of 72 participants (34 females and 38 males) underwent 3D total body imaging, resulting in the analysis of 27,622 individual nevi. Nevus characteristics, including size and distribution, were compared between sexes, with statistical adjustments for body surface area. Results Males exhibited significantly larger nevi than females across most body sites, particularly on the back and anterior torso. The average lesion diameter was 3.27 mm in males compared to 3.01 mm in females ( p < 0.001). Males were more likely to have nevi larger than 5 mm (OR = 1.65; 95% CI: 1.52–1.78), while females had a higher proportion of smaller nevi (2–3 mm). Females also showed a nonsignificant trend toward greater nevus density on the extremities. These differences remained significant after adjusting for body surface area. Conclusions Sex‐related differences in nevus phenotype, particularly in nevus size and distribution, are evident and not solely attributable to anatomical differences. The use of high‐resolution 3D imaging enhances phenotypic precision and supports the hypothesis that hormonal or developmental factors may contribute to sexually dimorphic nevus patterns.