title: Arachnoid cysts confined to the internal auditory canal or facial nerve canal.
abstract: OBJECTIVE
  To illustrate the morphological characteristics and pathological significance of arachnoid cysts confined to the internal auditory canal or facial nerve canal.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Three patients' cases were reviewed, and temporal bone sections examined histologically.
  
  
  RESULTS
  In this series, three intracanalicular arachnoid cysts were found in the internal auditory canal and one in the facial nerve canal. All lesions consisted of distinct, space-occupying cysts with a sharp boundary with surrounding tissues. They were thin-walled and compressed the surrounding nerve trunks to a variable degree. However, there was no indication that patients suffered meatal nerve dysfunction.
  
  
  CONCLUSIONS
  Arachnoid cysts can develop within the internal auditory canal or facial nerve canal. In our series, they were asymptomatic, which is quite different from most intracanalicular arachnoid cysts encountered in clinical practice.
authors.affiliation: Department of Otology and Neurotology, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.forename: K
authors.initials: K
authors.lastname: Kaga
authors.forename: M
authors.initials: M
authors.lastname: Sano
authors.forename: H
authors.initials: H
authors.lastname: Takegoshi
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000150:complications; D000328:Adult; D000368:Aged; D016080:Arachnoid Cysts / Q000175:diagnosis* / Q000473:pathology; D058070:Asymptomatic Diseases; D001344:Autopsy; D001943:Breast Neoplasms / Q000473:pathology; D007758:Ear, Inner / Q000473:pathology*; D005154:Facial Nerve / Q000473:pathology*; D017809:Fatal Outcome; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology; D006467:Hemophilia A / Q000150:complications; D006801:Humans; D020300:Intracranial Hemorrhages / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D009408:Nerve Compression Syndromes / Q000209:etiology; D009464:Neuroma, Acoustic / Q000150:complications / Q000175:diagnosis; D012189:Retrospective Studies; D013701:Temporal Bone / Q000473:pathology*; D014012:Tinnitus; D014390:Tuberculosis, Meningeal / Q000150:complications; D055815:Young Adult