Vestibular Schwannoma

Also known as: Acoustic Neuroma

Background

A vestibular schwannoma is a benign (non cancerous), usually slow growing, brain tumour and accounts for six to ten per cent of all brain tumours. Vestibular schwannomas affect approximately 1 in 70,000 persons per year. The cells that form a  vestibular schwannoma are called Schwann cells and make up the lining of the eighth cranial nerve as it passes through a tiny canal, which connects the inner ear to the brain. Unknown events lead to an overproduction of Schwann cells, which as they multiply, form a small tumour, which fills the canal.

Credits

Medical text written September 2010 by the Acoustic Neuroma Association. Approved September 2010 by Mr Nigel Mendoza, Consultant Neurosurgeon, Charing Cross Hospital, London, UK.

What are the symptoms?

Early symptoms can be easily overlooked, making diagnosis a challenge. The first symptom in over 90 per cent of patients is a reduction of hearing in one ear, sometimes accompanied by tinnitus. The loss of hearing is usually slight and worsens slowly, although sudden hearing loss has been known.

Other symptoms may be a feeling of fullness in the ear, but very rarely any pain. Unsteadiness and balance problems may occur and facial sensation may be affected, causing tingling and numbness. A large tumour can cause headaches due to a rise in pressure within the brain.

How is it diagnosed?

Physical examination may identify some signs such as unilateral (one sided) facial drooping or unsteadiness on walking, but a diagnosis of acoustic neuroma is usually made following a neurological assessment, taking the individual’s history and performing other tests such as a magnetic resonance imaging (MRI) scan and hearing tests.

How is it treated?

Monitoring – if the vestibular schwannoma is small and the patient has adjusted to living with the symptoms, then it may be appropriate to monitor the growth rate of the tumour through periodic MRI scans. It is not uncommon for vestibular schwannomas to show no significant growth when observed over a number of years.

Surgery – is often done by a neurosurgeon (brain surgeon) and a neurootologist (ear surgeon). Removal of the tumour may be approached from behind the ear (sub-occipital or posterior fossa), the mastoid and inner ear structures (translabyrinthine) or above the ear (middle fossa). The choice depends on the location and size of the tumour, degree of residual hearing and the surgeon’s operating preference.

Radiation – this is a non-invasive treatment and is used where the specialist considers it to be appropriate. Radiation does not remove the tumour but damages the DNA so that the cells forming the tumour cannot reproduce. The success or otherwise of the treatment takes about 12 months to two years to determine. A total of 90 per cent of tumours will be controlled with radiation but they will need long-term surveillance.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
There is a known association of vestibular schwannoma with neurofibromatosis  type 2 (NF2), which is a genetic disorder that is caused by a misprint in a single gene on chromosome 22.

Prenatal diagnosis
Not yet possible.

Is there support?

British Acoustic Neuroma Association (BANA)

Tel: 0800 652 3143
Email: admin@bana-uk.com
www.bana-uk.com

The Association is a Registered Charity in England and Wales No. 1024443. It provides information and support to people affected by acoustic neuroma and the interrelated conditons, symptoms and effects. The Association hosts a number of branch and support groups throughout the UK for members, their families and non-member guests to attend.

Group details last updated December 2014.

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