Risk Stratification Among Individuals Who Have Many Moles on Their Skin

Inclusion Criteria: * Patients ≥ 18 years of age * High-risk nevus phenotype (≥ 50 nevi (≥ 2mm in size) and ≥ 1 atypical nevus) * First presented to MSKCC for cutaneous melanoma-related care on or after April 2016 * Cases: diagnoses of unequivocal invasive cutaneous melanomas (AJCC Stages I-IV) confirmed by MSKCC pathology on or after April 2016 * Cases: completion of surgical treatment of primary melanoma * Ability to sign or verbally consent to the informed consent Exclusion Criteria: * Controls: Histopathologically borderline melanocytic tumors for which melanoma could not be excluded or that were treated as possible melanomas. * Known germline high-penetrance melanoma predisposition mutation (that is, CDKN2A, CDK4, and BAP1) * Cases: history of invasive cutaneous melanoma (AJCC Stages I-IV) not confirmed by MSKCC pathology * History of acrolentiginous type of cutaneous melanoma or history of mucosal melanoma * Cases and controls: prior administration of systemic medications known to modify nevus phenotype, including but not limited to: MEK inhibitors (trametinib, cobimetinib, etc.), BRAF inhibitors (vemurafenib, dabrafenib, etc.), and immunotherapy (pembrolizumab, nivolumab, atezolizumab, ipilimumab, etc.). Controls: history of Stage 0-IV melanoma confirmed by MSKCC pathology * History of limb amputation or other condition (e.g., tattoos, burns) per investigator discretion that would modify nevus phenotype * Physical inability to undergo total body photography or refle…