Giant Dilated Virchow Robin Spaces Causing Midbrain Compression and Obstructive Hydrocephalus

Virchow Robin spaces (VRSs) are normal perivascular spaces, lined with pia mater, around perforating arteries in the brain parenchyma that act as drainage pathways for interstitial fluid. Giant dilatation of VRS is rare and may produce multicystic giant lesions that can cause pressure effect on surrounding structures and can mimic cystic neoplasms. We describe a 12 year old boy with a giant dilated Virchow robin space centered on the midbrain (type 3- mesencephalic) who presented with lethargy and upbeat nystagmus.