Benign Schwann cell tumor of the vestibulocochlear nerve (CN VIII), usually at the cerebellopontine angle; causes progressive unilateral hearing loss with tinnitus.
Most common tumor of the cerebellopontine angle; can cause permanent hearing loss and even brainstem compression if untreated. Also, bilateral acoustic neuromas are a hallmark of neurofibromatosis type 2, a classic exam fact.
Gradually progressive unilateral hearing loss (sensorineural) and tinnitus in one ear are the classic presenting symptoms.
Imbalance or unsteady gait (due to vestibular nerve involvement) is common; true spinning vertigo is less frequent.
Large tumors can cause headaches and compress nearby nerves – leading to facial numbness (trigeminal nerve) or facial weakness (facial nerve) – and may even result in hydrocephalus (brainstem compression).
Suspect acoustic neuroma in any unilateral sensorineural hearing loss or persistent one-sided tinnitus.
Obtain an audiogram (hearing test) to confirm asymmetric sensorineural hearing loss in the affected ear.
Confirm the diagnosis with MRI with gadolinium of the internal auditory canal (gold standard). If MRI is contraindicated, consider CT with contrast or auditory brainstem response as alternatives.
Consult neurosurgery/otolaryngology for management once diagnosed. Decision between observation, stereotactic radiosurgery, or microsurgical removal depends on tumor size, growth rate, patient age, and hearing status.
second most common CPA tumor; dural-based mass that can mimic vestibular schwannoma (often has a dural "tail" on MRI)
Small tumor or minimal symptoms: observation with periodic MRI and audiometry (monitor growth).
Stereotactic radiosurgery (e.g., Gamma Knife) for moderate tumors or patients unfit for surgery — focused radiation to halt growth while preserving nerves.
Large or growing tumor: microsurgical resection (craniotomy) to remove the tumor; offers cure but risks hearing loss or facial nerve injury.
Bilateral acoustic neuromas = NF2 (mutation in the *NF2* tumor suppressor gene for merlin on chr22).
Any unilateral sensorineural hearing loss should be presumed an acoustic neuroma until proven otherwise—always get MRI.
New facial paralysis or facial numbness—indicates tumor enlargement compressing CN VII/V (urgent re-evaluation).
Signs of ↑ICP (severe headache, vomiting)—suggest hydrocephalus from brainstem compression (neurosurgical emergency).
Unilateral hearing loss or tinnitus → perform audiogram to assess for asymmetric sensorineural hearing loss.
Confirmed asymmetric SNHL → get MRI (with gadolinium) of internal auditory canal to look for vestibular schwannoma.
If tumor is detected → refer to specialist and choose management (observe vs radiation vs surgery) based on tumor size and patient factors.
If no tumor is found → pursue other causes of hearing loss (e.g., Meniere disease, chronic noise exposure, otosclerosis).
Middle-aged adult with months of progressive hearing loss and ringing in one ear, along with imbalance; MRI reveals a unilateral cerebellopontine angle tumor → acoustic neuroma (vestibular schwannoma).
Young patient with Neurofibromatosis type 2 and bilateral hearing loss → bilateral acoustic neuromas (NF2 hallmark).
Case 1
A 50‑year‑old man reports gradually worsening hearing in his right ear over a year, accompanied by constant ringing in that ear and unsteady balance.
Case 2
A 25‑year‑old with known **neurofibromatosis type 2** develops progressive hearing loss in both ears.
Medical illustration showing an acoustic neuroma (vestibular schwannoma) arising from the vestibulocochlear nerve.
