Primary melanocytic neoplasm

Primary melanocytic neoplasms of the CNS belong to the tumors of the meninges, further classified as diffuse melanocytosis, melanocytoma, malignant melanoma, and meningeal melanocytoma.

A primary CNS melanoma can be diagnosed after a positive cerebral biopsy, even if extensive dermatological, mucosal and ophthalmological examinations were inconclusive 1).

Intracranial malignant melanomas demonstrate a moderate to high intensity in T1WI and a low intensity in T2WI, while amelanotic melanomas demonstrate a low intensity in T1WI and a high intensity in T2WI 2) 3).

1)
Hayward RD. Malignant melanoma and the central nervous system. A guide for classification based on the clinical findings. J Neurol Neurosurg Psychiatry. 1976 Jun;39(6):526-30. PubMed PMID: 950562; PubMed Central PMCID: PMC492341.
2)
Isiklar I, Leeds NE, Fuller GN, et al. Intracranial metastatic melanoma: correlation between MR imaging characteristics and melanin content. Am J Roentgenol. 1995;165:1503–12.
3)
Vanzieleghem BD, Lemmerling MM, Van Coster RN. Neurocutaneous melanosis presenting with intracranial amelanotic melanoma. Am J Neuroradiol. 1999;20:457–60.