Teaching NeuroImages: Corkscrew medullary veins in active neurosarcoidosis

A 47-year-old man with a history of biopsy-proven sarcoidosis presented with 6 months of cognitive decline and incontinence. Neuroimaging was consistent with active neurosarcoidosis and notable for asymmetrical dilation and corkscrew appearance of the right medullary veins (figure). Medullary vein dilation is a recently described imaging pattern in neurosarcoidosis, seen in 33% of patients.1 The pathogenesis is uncertain but may result from perivenous inflammation or dysfunction of glymphatic drainage.1 Susceptibility-weighted imaging highlights the veins by localizing the paramagnetic signal of deoxygenated blood.2 Medullary vein dilation is a frequent finding in neurosarcoidosis, which can be used as one of the diagnostic criteria and can serve as a biomarker of disease activity.