title: Dural arteriovenous fistula after craniotomy for pilocytic astrocytoma in a patient with protein S deficiency.
abstract: BACKGROUND
  We report an unusual case, which may provide insight into the etiology and pathogenesis of dural arteriovenous malformation.
  
  
  METHODS
  A 24-year-old woman presented with hemorrhage into a pilocytic astrocytoma of the collicular plate. Angiography was normal and the tumor was surgically resected. She developed sigmoid sinus thrombosis and a transverse/sigmoid sinus dural arteriovenous fistula 11 months after this and was found to have protein S deficiency. The fistula was not treated. Angiography 4 years later was unchanged.
  
  
  CONCLUSIONS
  This report illustrates an acquired etiology of a dural arteriovenous fistula. To our knowledge this is the first reported case of postoperative sigmoid sinus thrombosis along with arteriovenous fistula in a patient with previously undetected protein S deficiency.
mesh_terms: D000328:Adult; D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D020785:Central Nervous System Vascular Malformations / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D003399:Craniotomy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007245:Inferior Colliculi / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D018455:Protein S Deficiency / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology; D011859:Radiography