# Vestibular schwannoma (acoustic neuroma)

Source: https://onco.cc/cancers/vestibular-schwannoma/  
OnCo record `vestibular-schwannoma` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A vestibular schwannoma is a benign growth on the balance and hearing nerve, deep in the skull. It is rarely dangerous, so many are simply watched with scans; growing tumours are treated with either an operation or a single precisely focused dose of radiation, and people with the inherited condition NF2, who develop tumours on both sides, can be helped by the drug bevacizumab.

## Summary

Vestibular schwannoma is a WHO grade 1 nerve sheath tumour arising from Schwann cells of the vestibular division of the eighth cranial nerve in the internal auditory canal and cerebellopontine angle. Sporadic tumours are unilateral and carry somatic NF2 inactivation; bilateral tumours define NF2-related schwannomatosis, the germline condition renamed in 2022 from neurofibromatosis type 2, which also causes meningiomas, spinal schwannomas and ependymomas. Presentation is progressive unilateral hearing loss, tinnitus and imbalance; large tumours compress the brainstem and cause hydrocephalus. Diagnosis is by MRI; biopsy is not needed.

Management has three arms. Observation with serial MRI is appropriate for small tumours because many do not grow, and hearing can be followed. Microsurgery through retrosigmoid, translabyrinthine or middle fossa approaches removes the tumour with facial nerve monitoring; it is favoured for large tumours with brainstem compression and in younger patients. Stereotactic radiosurgery at marginal doses of about 12 to 13 Gy controls the great majority of small and medium tumours with low facial nerve risk, and fractionated stereotactic radiotherapy or proton therapy is used for larger lesions. Leksell treated the first acoustic neuroma with the Gamma Knife in 1969, and radiosurgery has since displaced surgery for most small growing tumours. Hearing preservation is the outcome that most separates the options and depends on pre-treatment hearing and tumour size.

In NF2-related schwannomatosis the aim is to preserve hearing and function over a lifetime of multiple tumours. Bevacizumab produced tumour shrinkage and hearing improvement in progressive NF2 tumours (Plotkin and colleagues, NEJM 2009) and is used off label; brigatinib showed activity across NF2-related tumour types in the INTUITT-NF2 platform trial (2024), and cochlear or auditory brainstem implants restore hearing after bilateral loss. Radiosurgery is used more cautiously in NF2 because control rates are lower and there is a small concern about malignant change in a germline-predisposed nerve.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: Acoustic neuroma; Vestibular schwannoma; NF2-related schwannomatosis; Eighth nerve tumour
- Tags: subtype-page; cns
- Group: central nervous system
- Burden: A benign tumour found in roughly one in a thousand people over a lifetime, presenting with one-sided hearing loss; sporadic tumours are single, while NF2-related schwannomatosis causes bilateral tumours from young adulthood and is the hard form of the disease.
- Subtypes: Sporadic unilateral vestibular schwannoma (somatic NF2 loss); NF2-related schwannomatosis with bilateral vestibular schwannoma; Intracanalicular schwannoma (confined to the internal auditory canal); Cerebellopontine angle schwannoma with brainstem compression; Cystic vestibular schwannoma (faster growth, less predictable radiosurgery response)
- Biomarkers: Tumour size and growth on serial MRI (Koos grade); Pure-tone audiometry and word recognition (hearing class); Germline NF2 testing when bilateral, young or with other schwannomas or meningiomas; Facial nerve function (House-Brackmann grade) before and after treatment

## Standard of care

- Small tumour, stable or good hearing: Observation with MRI and audiometry, typically yearly; treatment on documented growth or hearing decline. ([Active surveillance](https://onco.cc/technologies/active-surveillance/), [MRI](https://onco.cc/technologies/mri/))
- Growing small or medium tumour: Stereotactic radiosurgery (Gamma Knife, CyberKnife or linac) at about 12 to 13 Gy, or fractionated stereotactic radiotherapy; microsurgery in younger patients or by preference. ([Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)](https://onco.cc/technologies/radiosurgery-srs/), [Gamma Knife](https://onco.cc/technologies/gamma-knife/), [CyberKnife robotic radiosurgery](https://onco.cc/technologies/cyberknife/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/))
- Large tumour with brainstem compression or hydrocephalus: Microsurgical resection with facial nerve monitoring, sometimes deliberately subtotal followed by radiosurgery to the remnant; shunting for hydrocephalus. ([Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)](https://onco.cc/technologies/radiosurgery-srs/), [MRI](https://onco.cc/technologies/mri/))
- NF2-related schwannomatosis, progressive tumour or falling hearing: Bevacizumab (off label, phase 2 evidence) to shrink tumours and improve hearing; brigatinib on INTUITT-NF2 evidence; hearing rehabilitation with cochlear or auditory brainstem implants; surgery and radiosurgery used selectively. ([Bevacizumab](https://onco.cc/drugs/bevacizumab/), [Brigatinib](https://onco.cc/drugs/brigatinib/))

## State of the art

- Radiosurgery controls most small vestibular schwannomas with a single outpatient treatment and has displaced surgery as the default for growing small tumours.
- Watchful waiting is legitimate first-line management because a large share of tumours never grow.
- Bevacizumab and, more recently, brigatinib are the first drugs to shrink NF2-related tumours, turning a surgical disease into one partly managed medically.

## Open problems

- No approved drug for NF2-related schwannomatosis; bevacizumab is off label and its effect wanes.
- Predicting which small tumours will grow, so that the rest can be left alone.
- Preserving hearing: each option trades tumour control against hearing and facial nerve function.
- Rare malignant transformation after radiosurgery in NF2 is not well quantified.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Vestibular_schwannoma
- Wikipedia: https://en.wikipedia.org/wiki/Vestibular_schwannoma
- Bevacizumab in NF2 vestibular schwannomas (NEJM 2009): https://doi.org/10.1056/NEJMoa0902579

## Connected records

- cancers: [Brain and spinal cord tumours (all types)](https://onco.cc/cancers/brain-tumours/), [Ependymoma](https://onco.cc/cancers/ependymoma/), [Meningioma](https://onco.cc/cancers/meningioma/), [Spinal cord tumours (intramedullary and intradural)](https://onco.cc/cancers/spinal-cord-tumours/)
- technologies: [Active surveillance](https://onco.cc/technologies/active-surveillance/), [CyberKnife robotic radiosurgery](https://onco.cc/technologies/cyberknife/), [Gamma Knife](https://onco.cc/technologies/gamma-knife/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/), [MRI](https://onco.cc/technologies/mri/), [Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)](https://onco.cc/technologies/radiosurgery-srs/)
- drugs: [Bevacizumab](https://onco.cc/drugs/bevacizumab/), [Brigatinib](https://onco.cc/drugs/brigatinib/)
- terms: [Stereotactic radiosurgery (SRS)](https://onco.cc/terms/stereotactic-radiosurgery/)

---
JSON: https://onco.cc/api/v1/entities/vestibular-schwannoma.json