Tumefactive Virchow-Robin spaces: A rare cause of obstructive hydrocephalus.

A middle-aged male presented with complaints of mild headache and unsteadiness of gait for past 2 years. His physical examination and lab results, including the cerebrospinal fluid (CSF) examination were unremarkable. Magnetic resonance imaging (MRI) of brain was done which revealed a cluster of cysts in the midbrain isointense to CSF on all sequences [Figures 1 and 2]. No enhancement of the cyst walls was seen on post-gadolinium images [Figure 3]. MR spectroscopy did not show any choline, lipid, or amino acid peak in the lesions. These were seen to cause mass effect on aqueduct of Sylvius and mild obstructive hydrocephalus. Review of MRI done before 2 years revealed the same lesions in the mesencephalothalamic region; no change in size or signal intensity was observed in the present scan. The final diagnosis was tumefactive Virchow-Robin spaces causing mild hydrocephalus. The patient was referred to neurosurgery department for further management. A VP shunt was placed with dramatic resolution of symptoms.

Figure 1

Axial T1-weighted images show cluster of cysts in the mesencephalic region isointense to cerebrospinal fluid (CSF)

Figure 2

Coronal fluid attenuated inversion recovery (FLAIR) image shows CSF isointense cysts in mesencephalothalamic region causing mild hydrocephalus. Periventricular hyperintense signal is due to transependymal seepage and/or microvascular ischemia

Figure 3

Coronal post-gadolinium T1-weighted images do not reveal any enhancement of cysts, consistent with the diagnosis of tumefactive perivascular spaces

The Virchow-Robin or perivascular spaces are pial-lined, fluid-filled spaces accompanying perforating arteries and venules. Typical perivascular spaces occur along lenticulostriate arteries above the anterior perforating substance and anterior commissure. They may occur less commonly in subcortical location, subinsular region, and cerebellum.[1] Rarely they may become enlarged (called tumefactive Virchow-Robin spaces) and cause mass effect and hydrocephalus (especially those found in mesencephalothalamic region); these need to be distinguished from cystic neoplasms.[2] Some authors have proposed the term Virchoma for enlarged mesencephalic perivascular spaces.[3] Tumefactive or cavernous dilation of Virchow-Robin spaces occurring in mesencephalothalamic region may be associated with hydrocephalus. The diagnostic features for tumefactive or cavernous dilation of Virchow-Robin spaces in this case are, an absence of signal from the lesion on the fluid attenuated inversion recovery (FLAIR) imaging, no abnormal signal in the adjacent neuroparenchyma, no contrast enhancement on post-gadolinium scans, and no change in size or appearance over 2 years. The differential diagnosis of tumefactive perivascular spaces includes cystic neoplasms, parasitic cysts, ventricular diverticulae, nonneoplastic neuroepithelial cysts, and mucopolysaccharidosis.[345] Extreme unilateral dilation of Virchow-Robin spaces may also be encountered.[6] Large Virchow-Robin spaces (VRS) have been associated with age, dementia, multiple sclerosis, trauma, hypertension, and incidental white matter lesions.[178] Surgical shunting of the hydrocephalus associated with VR spaces has produced variable clinical results (with improvement in gait disturbances, bradykinesia, and urinary symptoms). We conclude that mesencephalic tumefactive Virchow Robin spaces can cause obstructive hydrocephalus, and rare manifestations of a common entity should always be considered.