What is an acoustic neuroma?
Acoustic neuroma brain tumour is a sub-type of schwannoma that occurs in the inner ear, wrapping around the vestibular (auditory) nerve, situated in the inner ear. This type of tumour is also called vestibular schwannoma.
The vestibular nerve is one branch of the vestibulocochlear nerve, the other branch being the cochlear nerve. The vestibular nerve is responsible for carrying messages from your inner ear to your brain and is therefore related to your ability to hear, as well as contributing to your sense of balance and perception of body position.Read more Show less
Are acoustic neuroma low-grade (benign) or high-grade (malignant) brain tumours?
Almost all are classified as grade 1, which is the slowest growing type of tumour. They are often referred to as “benign”, but as the symptoms tend to get worse over time as the tumours increase in size, many patients and clinicians prefer to use the term “slow-growing” or “low-grade”.Read more Show less
How does an acoustic neuroma brain tumour develop?
Schwannoma is a type of tumour that develops from schwann cells. Schwann cells form what is called the myelin sheath, by wrapping themselves around peripheral nerves to provide protection and support.
What are the symptoms of acoustic neuroma?
Symptoms are caused when the tumour grows to a point where it puts pressure on the acoustic nerve or on adjacent nerves. This may include the facial nerve that control facial muscles, or trigeminal nerves that influence sensation in the face. They may sometimes also press on nearby blood vessels or other structures within the brain.
Symptoms may include one or more of the following:
- Hearing loss that becomes gradually (or occasionally suddenly) worse, usually on one side. This hearing loss may also fluctuate.
- Tinnitus: a buzzing or ringing noise in the ear, usually on one side
- Facial muscle weakness, numbness or pain
- Persistent headaches
- Weakness in the arms or legs
- Balance issues, especially if walking in the dark or on uneven ground
- Poor limb co-ordination (ataxia) on one side of the body
What causes an acoustic neuroma?
Most occur spontaneously. The reason why they occur is unclear, because there are so many factors that could potentially cause a fault in a gene and hence trigger a tumour. Acoustic neuromas are caused by changes in a gene called NF2 (which is a gene on chromosome 22 in our DNA).
A healthy gene in this position produces a tumour suppressor protein designed to control the growth of schwann cells, so when it doesn’t work properly, the schwann cells grow with a lack of control and co-ordination, hence forming a tumour.
Acoustic neuromas can also occur as part of genetic diseases called neurofibromatosis 2 (NF2) and schwannomatosis (SWN). Schwannomatosis tends to be diagnosed in early adulthood and can be preceded by chronic pain, sometimes in areas where there are no tumours, due to the fact that pain signals originating from nerves where tumours are causing pressure can sometimes be felt at distant sites within the body.
Only around 7% of people diagnosed with an acoustic neuroma also have neurofibromatosis 2. Anyone diagnosed with any form of neurofibromatosis would be transferred to a specialist team to ensure that patients are cared for by clinical experts in treating this condition.Read more Show less
What is the best treatment for acoustic neuroma?
Some grow so slowly that they are simply monitored using regular scans, and may not need to be treated. Others can grow rapidly and will be treated more quickly.
Surgery: Many acoustic neuroma can be completely removed by surgery, whilst others may be in positions where there is a risk of causing harm. In these cases, the priority for the neurosurgeon will be to ensure that they remove as much of the tumour as possible whilst avoiding any damage to the acoustic nerve.
If the tumour grows back, surgery may be offered again to reduce tumour size again.
Stereotactic radiotherapy: This is a highly targeted form of radiotherapy that may be used to treat small acoustic neuromas (usually less than 3cm diameter), dependent on their position.
Radiotherapy: Radiotherapy is rarely used for slow-growing forms of acoustic neuroma in order to avoid damage to the delicate nerves that they are wrapped around.
However for tumours classified as malignant, radiotherapy would be used to help prevent recurrence after surgery.
Chemotherapy: Chemotherapy is rarely used for slow-growing acoustic neuroma tumours because most chemotherapy drugs are designed to target cells that are dividing rapidly.
Molecular profiling: There is a lot of research in this area at the moment to clarify which molecular characteristics can be relied upon to guide treatment decisions. It also enables researchers to explore drugs that can target specific genetic mutations, leading in the future towards more effective, personalised treatment protocols.Read more Show less
How will we find a cure for acoustic neuroma?
Research we are funding across all of our Centres of Excellence will help lead towards finding a cure for a wide range of brain tumours.
Our University of Plymouth Centre of Excellence is Europe’s leading research institution for low-grade brain tumours, and has a strong focus on schwannoma, acoustic neuroma and neurofibromatosis 2.
They have developed an all-human cell model of schwannoma, developed from tissue samples donated by patients who have undergone surgery. This model is being used in laboratory experiments designed to learn more about the causes and behaviour of schwannomas, and ultimately to find a cure by developing targeted drug therapies.
Scientists at our Brain Tumour Research Centre of Excellence in the University of Portsmouth also collaborate with the University of Plymouth Centre of Excellence on some aspects of schwannoma research.
Their findings can be used to develop treatments that target particular molecular pathways and hence influence the processes that they control. They have also developed models of the blood brain barrier that support research into drug therapies for all types and grades of brain tumours.
We also fund BRAIN UK at Southampton University, the country’s only national tissue bank providing crucial access to brain tumour samples for researchers from the archives of clinical neuroscience centres in the UK, effectively covering about 90% of the UK population, and an essential component in the fight to find a cure for acoustic neuroma.Read more Show less
Page last updated November 2018. Next review September 2019.