Sarcoidosis is a systemic granulomatous disease of unknown origin presentating at any age, but most commonly between 20 and 40. The CNS presentation occurs as either leptomeningeal involvement or as a granulomatous mass.
Meningeal disease can be focal or diffuse.
Diffuse meningeal involvement is more common with diffuse, gyriform enhancement of the leptomeninges with a predilection for the basilar regions with resultant hydrocephalus. Parenchymal disease can manifest as diffuse or multifocal periventricular white matter lesions which are hyperintense on T2W images and enhance. Cortical and subcortical nodules also occur with a predilection for the skull base, pituitary, pons and hypothalamus. Spinal cord involvement includes granulomatous infiltration of the cord or leptomeninges. Again the lesions are hyperintense on T2W images and enhance uniformly on T1W images.