title: Giant tumefactive perivascular spaces.
abstract: OBJECTIVE
  The brain perivascular spaces (PVSs) are pial-lined, interstitial fluid-filled structures that accompany penetrating arteries. When enlarged, they may cause mass effect and can be mistaken for more ominous pathologic processes. The purpose of this study was to delineate the broad clinical and imaging spectrum of this unusual condition.
  
  
  METHODS
  Thirty-seven cases of giant PVSs were identified from 1988 to 2004 and were retrospectively reviewed. Clinical data collected included patient demographics, presenting symptoms, and follow-up. Histopathologic data were reviewed when available. Images were evaluated for size and location of the giant PVSs, associated mass effect, hydrocephalus, adjacent white matter changes, and contrast enhancement.
  
  
  RESULTS
  There were 24 men and 13 women with an age range of 6-86 years, (mean 46 years). The most common presenting feature was headache (15 patients). Thirty-two cases had multilocular clusters of variably sized cysts. Five lesions were unilocular. All lesions had signal intensity comparable to CSF and did not enhance. The most common location for the giant PVSs was the mesencephalothalamic region (21/36). Fourteen were located in the cerebral white matter; two were in the dentate nuclei. Nine giant mesencephalothalamic PVSs had associated hydrocephalus, which required surgical intervention.
  
  
  CONCLUSIONS
  Giant tumefactive PVSs most often appear as clusters of variably sized cysts that are isointense relative to CSF and do not enhance. They are most common in the mesencephalothalamic region and may cause hydrocephalus. Although they may have striking mass effect, giant PVSs should not be mistaken for neoplasm or other diseases.
authors.affiliation: Department of Radiology, University of Utah, 1A71 University Hospital, 50 N. Medical Drive, Salt Lake City, UT 84132, USA.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Salzman
authors.forename: Anne G
authors.initials: AG
authors.lastname: Osborn
authors.forename: Paul
authors.initials: P
authors.lastname: House
authors.forename: J Randy
authors.initials: JR
authors.lastname: Jinkins
authors.forename: Adam
authors.initials: A
authors.lastname: Ditchfield
authors.forename: James A
authors.initials: JA
authors.lastname: Cooper
authors.forename: Roy O
authors.initials: RO
authors.lastname: Weller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000473:pathology* / Q000601:surgery; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies