Clinical, Laboratory, and Epidemiologic Characterization of Individuals and Families at High Risk of Melanoma

* INCLUSION CRITERIA: * On referral, persons \>=4 weeks old of any sex, race or ethnicity will be considered for inclusion in the study because of the criteria noted below. * Affected: An individual who meets any of the following criteria will be eligible to participate in this study: * personal medical history of melanoma of an unusual type, pattern, or number diagnosed at any age; or, * known or suspected factor(s) predisposing to melanoma, either genetic or congenital factors (giant congenital nevi, dysplastic nevi, Spitzoid tumors), or unusual demographic features (e.g., very young age of onset, multiple melanomas, previous history of heritable retinoblastoma, Hodgkin's disease, lymphoma, immunodeficiency syndrome, or organ transplant). * Ability of the individual or their parent or legal guardian, to understand, and their willingness to provide informed consent. * Unaffected: An individual who meets any of the following criteria will be eligible to participate in this study: * family medical history of melanoma of an unusual type, pattern, or number; or, * known or suspected factor(s) predisposing to melanoma, either genetic or congenital factors (giant congenital nevi, dysplastic nevi. Spitzoid tumors), or unusual demographic features (e.g., very young age of onset, multiple melanomas, previous history of heritable retinoblastoma, Hodgkin's disease, lymphoma, immunodeficiency syndrome, or organ transplant). * Ability of the individual or their parent, or legal guardian to understand, and their willingness to provide informed consent. * Personal and family medical history must be verified through questionnaires, interviews, and review of pathology slides and medical records. EXCLUSION CRITERIA: * Referred individuals and families for whom reported diagnoses cannot be verified; * Inability to provide informed consent