Neurocutaneous Melanocytosis Registry

This study will involve collecting information about the regular medical care you receive for large cutaneous melanocytic nevi (LCMN) or neurocutaneous melanocytosis (NCM).

Inclusion Criteria: * Patients with LCMN, defined as: * Dark-colored patch of skin present at birth * Can be located anywhere on the individual's skin * May include satellite lesions * May be associated with hypertrichosis OR, in absence of cutaneous involvement: * histologically or radiographically confirmed CNS melanocytosis. * Any age at diagnosis. * Signed informed consent by a patient, or parent/legal guardian. * Deceased patients can be included provided that parent/legal guardian is contacted at least 6 months after the death of the child and not on the child's birthday or anniversary of death. Pathology review at MSK is not mandatory to confirm the diagnosis of LCMN or NCM. We will not require pathology analysis of leptomeningeal deposits in patients where characteristic skin lesions are present and melanosis of the meninges is radiographically evident. However, if pathology samples have already been obtained as part of a patient's evaluation and treatment at another institution, tissue samples will be requested for review and confirmation of the diagnosis. Exclusion Criteria: * Informed consent has not been provided.