title: Enlargement of a vestibular schwannoma after stereotactic radiotherapy.
abstract: BACKGROUND
  Radiosurgery has been increasingly advocated as a primary treatment for vestibular schwannoma (VS), and recently fractionation of the dose has been proposed as a method to decrease the risk of radiation injury when treating larger tumors.
  
  
  METHODS
  The authors describe a 48-year-old woman who presented with right-sided hearing loss and new-onset tinnitus, with a progressive decrease in facial sensation. The diagnosis of a large right cerebellopontine angle VS was made on magnetic resonance imaging (MRI). The patient was treated with a course of fractionated stereotactic radiotherapy (SRT) (5 treatments of 4 Gy to the 90% isodose line over a 3-week period).
  
  
  RESULTS
  Six months after the initiation of therapy, her symptoms increased, and a repeat MRI scan demonstrated that her tumor had increased in size, producing significant brainstem compression. She then underwent complete surgical resection of the tumor, with resolution of her symptoms.
  
  
  CONCLUSIONS
  Stereotactic radiosurgery has been effective in controlling small VSs with low complication rates. Larger tumors pose a risk for increasing in size and producing symptoms from mass effect with SRT. There are at present limited data demonstrating safety and efficacy of fractionated SRT for the treatment of larger tumors.
authors.affiliation: Department of Neurosurgery, New York Medical College, Valhalla and New York, NY, USA.
authors.forename: W T
authors.initials: WT
authors.lastname: Couldwell
authors.forename: A L
authors.initials: AL
authors.lastname: Mohan
mesh_terms: D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery; D012720:Severity of Illness Index; D017211:Treatment Failure