EN4.12 | Acoustic Neuroma — Summary & Reflection

KEY TAKEAWAYS

Acoustic neuroma (vestibular schwannoma) is a benign tumour arising from Schwann cells of the vestibular nerve at the Obersteiner-Redlich zone in the internal auditory canal. It is the commonest CPA tumour (~80%). Key points:

• Presentation: unilateral progressive SNHL + unilateral tinnitus + mild vestibular disturbance; facial numbness and weakness are late signs; bilateral tumours = NF2.
• Audiological pattern: retrocochlear — rollover on speech audiometry, absent/reduced stapedial reflex, prolonged ABR wave V latency, caloric canal paresis.
• Gold standard investigation: MRI brain with gadolinium (thin-section IAC sequences) — shows enhancing ice-cream cone mass.
• Differential: meningioma (dural base, calcification, no IAC erosion), epidermoid (DWI restriction, no enhancement), facial schwannoma (rare).
• Management options: (1) observation for small/stable tumours; (2) radiosurgery for ≤3 cm with good control rates (~90–95%); (3) microsurgery via translabyrinthine (no hearing), retrosigmoid (hearing possible), or middle fossa (small, hearing preservation) approaches.
• Surgical priority: facial nerve preservation — monitored intraoperatively, graded by House-Brackmann scale.

REFLECT

Think about the patient in the opening scenario — a 38-year-old with 2 years of unilateral tinnitus and gradually worsening hearing, whose symptoms were attributed to headphones and stress. At what point should this patient have been investigated further? What barriers (patient-side and clinician-side) can delay the diagnosis of acoustic neuroma, and what would you do differently as the clinician who eventually sees him? Consider also the psychological impact on a patient of being told they have a 'brain tumour' that is benign and slow-growing — how would you frame the three management options in a consultation to support informed decision-making?