Primary Central Nervous System Melanoma (pCNSM) and Treatment Protocols: A Literature Review

Background: Melanocytes, responsible for melanin production, originate from the neural crest and can give rise to malignant tumors known as melanoma. Primary Central Nervous System Melanoma (pCNSM) is rare, with an incidence of 0.005 cases per 100,000 individuals annually. Considering its rare occurrence and the variations in tumor biology, a comprehensive treatment strategy has not yet been introduced. Immunotherapy is an emerging treatment avenue warranting further exploration. Objectives: In this review, we conducted an extensive literature review on patients with pCNSM, including the brain and spine, to determine the characteristics and most successful treatment protocol for pCNSM. Materials and Methods: A review of all published articles from 1980 to 2023 was done including PubMed and Google Scholar articles, multiple published case studies, and the Archives of the American Institute for Radiologic Pathology. Results: During our review we found 138 articles with 148 pCNSMs (77 cases of brain and 71 cases of spinal primary melanoma) spanning from 1980 to 2023. The vast majority of patients (95%) underwent therapeutic gross total or partial resection of the tumors followed by radiotherapy. Only two cases with brain melanomas underwent immunotherapy. The treatment strategies of primary brain melanomas were similar to those of primary spinal melanoma (PSM) but exhibited better outcomes in PSM cases. Conclusion: Our findings suggest surgical intervention, followed by adjuvant radiotherapy + immunotherapy, yields favorable outcomes in PSM cases but not in primary brain melanomas. Further multicentric studies are needed to explore alternative, more effective treatment modalities.