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Neuroradiology Case of the Week

Case 183

Farhad Farzanegan, MD, and Per-Lennart Westesson, MD, PhD, DDS

Clinical Presentation: Patient is a 41-year-old male, with prior history of head trauma, with recent seizure.

Radiological Findings: A non-enhancing lesion is seen in region of left basal ganglia, with signal similar to CSF.

Differential Diagnosis: Vacuolated lacune, cystic neoplasm

Diagnosis: Virchow-Robin space

Discussion: Virchow-Robin spaces are invaginations of the subarachnoid space into the brain associated with leptomeningeal vessels; these are extensions of the subarachnoid spaces in the form of a sheath of pial cells that surround small arterial and partly also venous vessels down to the capillary level. This sheath divides the subarachnoid space into an inner section (between vessel and pia) that takes the role of extracerebral lymphatic drainage, and an outer part (between pia and arachnoid). Dilated perivascular spaces occur in characteristic locations, typically in the basal ganglia, around the atria, near the anterior commissure, in the corona radiata, centrum semiovale, periinsular region, and in the middle of the brain stem, medial and posterior to the reticular portion of the substantia nigra. Usually they follow the intensity of CSF. Occasionally, gliosis may be associated with these spaces. A vacuolated lacune may simulate a Virchow-Robin space on FLAIR/PDWI.
      Virchow-Robin spaces tend to enlarge with age and hypertension as the vessels within the space become more ectatic. Dilated Virchow-Robin spaces in young immunosuppressed patients is concerning for possibility of intracranial cryptococcus infection.

References:

1. Latchaw, RE. Imaging of the Nervous System. Elsevier Mosby. 2005; 1248.
2. Grossman RI. Neuroradiology: The Requisites, 2nd ed. Mosby. 2003; 311, 345