Usefulness of Neuromelanin Sensitive MRI for En Plaque Meningeal Melanocytoma Involving the Cavernous Sinus: A Case Report

Intracranial meningeal melanocytoma is a rare tumor. Here, we report a case of pathologically diagnosed en plaque meningeal melanocytoma involving the cavernous sinus along with a review of the pertinent literature. A 35-year-old female presented with progressing left oculomotor nerve palsy and melanosis oculi. Radiological examinations revealed a lesion spreading in an en plaque fashion and involving the left cavernous sinus, which was hyperintense on T(1)-weighted magnetic resonance imaging (MRI), and hypointense on T(2)-weighted MRI. The lesion was partially excised following a histopathological diagnosis of meningeal melanocytoma. For follow-up of the residual lesion, neuromelanin sensitive MRI was introduced, and it provided better contrast between the lesion and surrounding intracranial normal tissue than conventional T(1)-weighted MRI with or without gadolinium. The lesion remained stable without any growth for 3 years post-surgery. Neuromelanin sensitive MRI may be the method of choice for the follow-up of meningeal melanocytoma.