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What is a Meningioma?
Most brain tumours are named after the type of cells from which they develop. A meningioma is a tumour of the meninges, which are the protective membranes around the brain and spinal cord. A meningioma can start in any part of the brain or spinal cord, but the most common sites are the cerebral hemispheres of the brain, made up of the four lobes. Sometimes however, they can grow in the CP Angle, making them much more difficult to deal with, due to their proximity in relation to the facial, cranial and other nerves in that area.
Most meningiomas are benign, and malignant meningiomas are fortunately extremely rare. Meningiomas make up nearly 20% of all primary brain tumours. They are most likely to be found in middle-aged or elderly adults, but ironically they are the most common type of brain tumour in children. Meningiomas are more common in females than in males. As with most brain tumours, the cause of a meningioma is unknown.
Signs and symptoms
Meningiomas are usually slow-growing tumours and the main symptoms arise from increased pressure within the skull (raised intracranial pressure). This may be due to a blockage in the ventricles (fluid-filled spaces of the brain) that leads to a build-up of cerebrospinal fluid (CSF). CSF is the fluid that surrounds and protects the brain and spinal cord. The increased pressure may also be caused by swelling around the tumour itself.
Raised intracranial pressure can cause headaches, sickness (vomiting) and visual problems. Changes in behaviour and personality are general signs of a brain tumour. Epileptic fits can be an early symptom.
Meningiomas can grow in different parts of the brain and symptoms will relate to the area of the brain that is affected. A tumour in the frontal lobe of the brain may cause gradual changes in mood and personality. There may also be paralysis on one side of the body (hemiparesis). If the left side of the brain is affected, there may be problems with speech, such as slurring or muddling of words. A tumour in the temporal lobe of the brain may cause problems with coordination and memory loss. If the parietal lobe of the brain is affected, writing and other such activities may be difficult. Hemiparesis may also be present. Fits (seizures) often occur in people with a meningioma. Meningiomas can sometimes cause single sided deafness, and are often initially considered as a tumour known as Acoustic Neuroma.
Tests and investigations
In order for the doctors to plan your treatment, they need to find out as much as possible about the type, position and size of the tumour. This is done through a number of tests and investigations:
Neurological examinations (nerve tests)- Usually, you will have a neurological examination to assess any effect of the tumour on your nervous system.
CT (computerised tomography) scan- A CT scan takes a series of x-rays, which are fed into a computer to build up a detailed picture of your brain. The test itself is completely painless, but you will have to lie still for about 10–30 minutes. A CT scan can find the exact position and size of the tumour.
MRI (magnetic resonance imaging) scan- This test is similar to a CT scan, but uses magnetism instead of x-rays to build up cross-sectional pictures of your brain. During the test you will be asked to lie very still on a couch inside a large metal cylinder that is open at both ends. The whole test may take up to an hour. It can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan, which is also very noisy. You will be given earplugs or headphones to wear.
Angiogram- This test involves an injection of a dye to show up the blood vessels in the brain. The dye is injected through a thin, flexible tube (catheter) that is inserted into an artery in the groin, arm or neck. A series of x-rays are taken. Your nurse or doctor will explain this test to you in more detail.
Biopsy- To confirm the exact type of tumour, a sample of cells may be taken from the tumour and examined under a microscope. Your doctor will discuss with you whether this is necessary in your case, and what the operation involves. Meningiomas can usually be clearly shown by scans and so a biopsy is rarely necessary.
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