title: Giant Mesencephalic Dilated Virchow Robin Spaces Causing Obstructive Hydrocephalus Treated by Endoscopic Third Ventriculostomy.
abstract: BACKGROUND
  Virchow Robin spaces (VRSs) are perivascular spaces that act as drainage pathways for interstitial fluid. Dilatation of VRSs is visible on magnetic resonance images in asymptomatic individuals. However, giant dilatation of VRSs (dVRSs) is very rare. Such giant dVRSs may produce a pressure effect on surrounding structures and can be confused with more sinister conditions such as cystic neoplasm.
  
  
  METHODS
  We describe a 30-year-old man who presented with complaints of headache, poor attention and concentration, forgetfulness, polyuria, urinary incontinence for past 3 years and hypersomnia for 3 months. He was found to have a multicystic lesion in the midbrain with extension into the third ventricle, causing hydrocephalus due to aqueductal obstruction. Although at first look, the radiologic features suggested a cystic neoplasm, a careful magnetic resonance imaging evaluation helped to establish the correct diagnosis of dVRS. Endoscopic third ventriculostomy resolved his symptoms.
  
  
  CONCLUSIONS
  Dilatation of VRS may produce multicystic giant lesions that can easily be confused with other pathologic condition that have a completely different prognosis and management. Knowledge about the existence of such an entity and their radiologic features is important to prevent such misdiagnosis and mismanagement in the form of biopsy/excision, which can have devastating consequences.
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India. Electronic address: aman_jagdevan@yahoo.co.in.
authors.forename: Amandeep
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Rishab
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Department of Neuroradiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Ajay
authors.initials: A
authors.lastname: Garg
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Bhawani S
authors.initials: BS
authors.lastname: Sharma
mesh_terms: D000328:Adult; D003560:Cysts / Q000473:pathology / Q000601:surgery; D004108:Dilatation, Pathologic / Q000473:pathology*; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology / Q000523:psychology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000473:pathology*; D013346:Subarachnoid Space / Q000473:pathology*; D020542:Third Ventricle / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D014696:Ventriculostomy / Q000379:methods*
keywords: Dilated; Giant; Mesencephalic; Virchow Robin spaces