Giant Mesencephalic Dilated Virchow Robin Spaces Causing Obstructive Hydrocephalus Treated by Endoscopic Third Ventriculostomy.

Abstract

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. 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. 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.