Hydrocephalus due to extreme dilation of Virchow-Robin spaces.

Virchow-Robin spaces (VRS) are extensions of the subarachnoid space surrounding perforating blood vessels entering the brain parenchyma. VRS are fluid filled, but almost virtual and only visible on MRI of the brain when dilated. Such dilations are commonly asymptomatic. In rare cases, extreme dilations can be observed; the clinical repercussions of which remain unclear. We report the case of a patient presenting symptoms of normal pressure hydrocephalus due to extreme VRS mesencephalon dilations.