title: Vestibular schwannoma: 825 cases from a 25-year experience.
abstract: BACKGROUND
  Acoustic nerve tumors have been recognized as a clinico-pathologic entity for at least 200 years, and they represent 90% of cerebellopontine angle diseases. Histologically, the tumors are derived from Schwann cells of the myelin sheath, with smaller tumors consisting of elongated palisade cells, while in large tumors, cystic degeneration can be found in the central areas, possibly due to deficient vascularization. We retrospectively reviewed 825 cases of vestibular schwannomas, reported between January 1984 and August 2006, in which the patients underwent surgery to remove the tumor.
  
  
  OBJECTIVE
  To evaluate signs, symptoms, aspects of clinical diagnosis, including the results of audiological and imaging studies, and surgical techniques and complications.
  
  
  METHODS
  A retrospective chart review. The medical records of all patients undergoing surgical treatment for schwannoma during the period indicated were reviewed.
  
  
  CONCLUSIONS
  Hearing loss was the first symptom reported in almost all cases, and tumor size was not proportional to the impairment of the auditory threshold. The surgical techniques allowed safe preservation of facial function. In particular, the retrolabyrinthine route proved useful in small tumors, with 50% preservation of hearing.
authors.affiliation: Specialist ENT. Physician Group Otology HCFMUSP.
authors.forename: Mariana Hausen
authors.initials: MH
authors.lastname: Pinna
authors.affiliation: Full Professor. Head of Clinical Otolaryngology, University of São Paulo School of Medicine. Chief of Otology, HCFMUSP.
authors.forename: Ricardo Ferreira
authors.initials: RF
authors.lastname: Bento
authors.affiliation: Full Professor, Division of Clinical Otolaryngology, HCFMUSP.
authors.forename: Rubens Vuono de Brito
authors.initials: RV
authors.lastname: Neto
keywords: acoustic; cranial nerve neoplasms; neuroma; vestibulocochlear nerve diseases