A 13-Year-Old Girl Affected by Melanocytic Tumors of the Central Nervous System—The Case

Primary intracranial melanoma is a very rare brain tumor, especially when accompanied by benign intramedullary melanocytoma. Distinguishing between a primary central nervous system (CNS) lesion and metastatic melanoma is extremely difficult, especially when the primary cutaneous lesion is not visible. Here we report a 13-year-old girl admitted to the Neurosurgery Department of the Institute of Polish Mother's Health Centre in Lodz due to upper limb paresis. An intramedullary tumor of the cervical C3-C4 and an accompanying syringomyelic cavity C1-C7 were revealed. The child underwent partial removal of the tumor due to the risk of damage to spinal cord motor centers. The removed part of the tumor was diagnosed as melanocytoma. Eight months later, a neurological examination revealed paresis of the right sixth cranial nerve, accompanied by bilateral optic disc edema. Diagnostic imaging revealed a brain tumor. The girl underwent resection of both detected the tumors and an additional satellite lesion revealed during the surgery. The removed tumors were diagnosed as malignant melanomas in pathomorphological examination. Molecular analysis revealed <i>NRASQ61K</i> mutation in both the intracranial and the intramedullary tumor. It should be noted that in cases where available evidence is inconclusive, an integrative diagnostic process is essential to reach a definitive diagnosis.