Original ArticlesMesencephalothalamic Giant Virchow-Robin Space Causing Obstructive HydrocephalusBaldawa, Sachin Sampat MBBS, MS; Easwer, Hariharan Venkat MBBS, MCh; Nair, Suresh MBBS, MCh; Menon, Girish MCh, DNBAuthor Information Department of Neurosurgery, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, India The authors declare no conflict of interest. Reprints: Hariharan Venkat Easwer, MBBS, MCh, Department of Neurosurgery, SCTIMST, Trivandrum, 695011, India (e-mail: firstname.lastname@example.org). Neurosurgery Quarterly: August 2011 - Volume 21 - Issue 3 - p 214-218 doi: 10.1097/WNQ.0b013e318215c8a5 Buy Metrics Abstract Virchow-Robin (VR) spaces are well-defined, normal pia-lined spaces along the walls of perforating arteries as they course in the brain parenchyma. These spaces are <2 mm in size and are similar to cerebrospinal fluid (CSF) intensity on all pulse sequences. Dilated VR spaces are part of normal aging process. When VR spaces assume large bizarre, multicystic configuration, they are called as giant perivascular spaces and can be mistaken for other intracranial cystic space occupying lesions. When located in the mesencephalon-thalamic region, they produce acute hydrocephalus, which necessitates CSF diversion. We report a rare case of giant VR space in the mesencephalon-thalamic region causing symptoms related to obstruction of CSF flow due to aqueduct compression. © 2011 Lippincott Williams & Wilkins, Inc.