title: Venous lesions as a cause of sylvian aqueductal obstruction: case report.
abstract: OBJECTIVE
  The cases of two patients who presented with sylvian aqueductal obstruction caused by venous lesions (an ectatic vein and a developmental venous anomaly, which are uncommon causes of obstructive hydrocephalus) are reported.
  
  
  METHODS
  A 42-year-old man presented with chronic headache and behavior abnormalities. Magnetic resonance imaging revealed supratentorial ventricular dilation caused by an obstruction of the sylvian aqueduct by a developmental venous anomaly. An 18-year-old man complained of intermittent headaches. The magnetic resonance imaging scan disclosed aqueductal stenosis-type hydrocephalus secondary to an ectatic vein.
  
  
  METHODS
  Both patients underwent endoscopic third ventriculostomy and recovered well. During the procedures, the aqueductal obstruction by venous elements could be seen clearly.
  
  
  CONCLUSIONS
  Venous anomalies may cause obstructive hydrocephalus and can be suspected in cases of chronic and intermittent headaches. Endoscopic third ventriculostomy is an effective treatment.
authors.affiliation: Division of Neurosurgery, Federal University of Minas Gerais, Belo Horizonte, Brazil. agjg@zaz.com.br
authors.forename: Alexandre V
authors.initials: AV
authors.lastname: Giannetti
authors.forename: Rachael B M
authors.initials: RB
authors.lastname: Rodrigues
authors.forename: Felipe P
authors.initials: FP
authors.lastname: Trivelato
mesh_terms: D000293:Adolescent; D000328:Adult; D020787:Central Nervous System Venous Angioma / Q000150:complications / Q000473:pathology* / Q000601:surgery; D002535:Cerebral Aqueduct / Q000098:blood supply* / Q000473:pathology* / Q000601:surgery; D002550:Cerebral Veins / Q000002:abnormalities*; D006261:Headache / Q000209:etiology; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology; D018810:Magnetic Resonance Angiography; D008297:Male; D020542:Third Ventricle / Q000473:pathology / Q000601:surgery; D014696:Ventriculostomy