Tumefactive perivascular spaces
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Tumefactive perivascular spaces (TPVS) is a rare finding of enlargement of perivascular spaces. It is important to recognize this condition as it can be easily mistaken for a neoplasm and also rarely local mass effect from TPVS can result in a complication.
Small case series of patients have also shown headache to be a common complaint in TPVS patients 1.
Perivascular spaces also known as Virchow-Robin spaces are potential spaces lined by pia mater, which surround the penetrating arterioles and extend into the brain parenchyma for variable distances. Perivascular spaces contain interstitial fluid.
In rare circumstances these perivascular spaces can be enlarged, "tumefactive", which can cause mass effect upon the surrounding structures.
A special type of perivascular spaces occur in the anterior temporal lobe and can mimic cystic tumors with peripheral edema. These are discussed separately: anterior temporal lobe perivascular spaces 2-3.
Although TPVS is a rare entity, MRI features are characteristic. Cluster of uniform or variable-sized cysts which follows CSF signal intensity on all MRI sequences 1. The orientation of the cyst may follow a radial pattern that is oriented in the direction of the perforating arterioles.
Coronal image is most useful in demonstrating the radial orientation of basal ganglia and thalamus TPVS along the direction lenticulostriate perforators. Gliosis may be seen in the adjacent white matter with minor increase signal intensity on the T2 or FLAIR sequence 1. No enhancement should be demonstrated 1.
Midbrain TPVS is oriented in the direction of the thalamostriate perforators and these may be more oval in configuration on the axial image. Rare complications of cerebral aqueduct stenosis with obstructive hydrocephalus have been reported in the literature 1.
- 1. Salzman KL, Osborn AG, House P et-al. Giant tumefactive perivascular spaces. AJNR Am J Neuroradiol. 2005;26 (2): 298-305. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 2. Rawal S, Croul SE, Willinsky RA et-al. Subcortical cystic lesions within the anterior superior temporal gyrus: a newly recognized characteristic location for dilated perivascular spaces. AJNR Am J Neuroradiol. 2014;35 (2): 317-22. doi:10.3174/ajnr.A3669 - Pubmed citation
- 3. Lim AT, Chandra RV, Trost NM et-al. Large anterior temporal Virchow-Robin spaces: unique MR imaging features. Neuroradiology. 2015;57 (5): 491-9. doi:10.1007/s00234-015-1491-y - Pubmed citation