The study population will consist of three categories of patients: (1) infants and children with large congenital melanocytic nevi, (2) adults with numerous (less than 100) melanocytic nevi, and (3) patients with primary malignant melanoma. Establishment of the Pigmented Lesion Clinic required for the execution of this protocol will provide a mechanism for the evaluation of patients with numerous or unusual pigmented lesions, and for the entry of eligible patients into ongoing therapeutic trials for malignant melanoma. As the study progresses, it is anticipated that a substantial amount of formalin-fixed nevus and primary melanoma tissue with a high-degree of clinical annotation will be collected. As a secondary objective , the availability of this collection will be useful to support studies designed to evaluate new markers and techniques for the diagnosis of melanoma and atypical nevi, and for incorporation into a tissue microarray that will be available to the melanoma research community for target foundation validation.