Vestibular Schwannoma

Rare, benign tumour of the CN VIII nerve sheath that arises in internal auditory meatus

Aetiology

  • Equal sex distribution
  • Aetiology unknown but may be associated with extensive exposure to excessively lound noise
  • If bilateral and young, consider neurofibromatosis type 2

Pathophysiology

  • Associated with vestibular portion of CN VIII
  • Occur within temporal bone, represent 80-90% of cerebellopontine angle tumours
  • 95% are sporadic and unilateral
  • Gross appearance - circumscribed tan/white/yellow mass
  • Histology - encapsulated, two growth patterns (Antoni A and Antoni B)

Clinical presentation

  • Progressive sensorineural unilateral hearing loss and tinnitus
  • Imbalance in larger tumours
  • Facial numbness can occur due to compression of the trigeminal nerve as the tumour enlarges

Investigations

  • MRI

Management

  • Surgical excision is the definitive management
  • Small lesions that are not growing may be monitored (MRI) - initially with a 6 month interval