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9 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
A vestibular schwannoma is a benign brain tumour, a 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.
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.
| Setting | Approach | Guideline |
|---|---|---|
| Small tumour, stable or good hearing | Observation with MRI and audiometry, typically yearly; treatment on documented growth or hearing decline. | not mapped |
| 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. | not mapped |
| 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. | not mapped |
| 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. | not mapped |