A meningioma is a tumour of the meninges, the outer membrane sheath covering the brain and spine. They can occur in any part of the brain or spinal cord but the commonest sites are at the surface of the brain, either over the top or at the skull base. Meningiomas do not spread. 90% of meningiomas are benign (non-cancerous), 6% are atypical, and 2% are malignant. Due to their slow-growth they do not always require immediate treatment and may be monitored over time. Although these are invariably slow growing and benign tumours, they can often cause significant symptoms due to their compressing and distorting the outer surface of the brain underneath where they are growing and can cause disability and even be life threatening. A meningioma described as atypical is likelier to re-grow.
Sometimes they may not be detected until of a significant size, sometimes out of the range that is suitable for Gamma Knife treatment. However, Gamma Knife can still play a role in the control of these tumours as it can either be used as the primary treatment for smaller lesions, or after surgery where complete removal was not possible or if a tumour has recurred post-surgery.
Symptoms of Meningiomas
Meningioma symptoms vary a lot, depending on where in the brain they are growing. Signs and symptoms typically begin gradually and may be very subtle at first and may include:
- Headaches that worsen with time
- Changes in vision, such as seeing double or blurriness
- Hearing loss or ringing in the ears
- Memory loss
- Loss of smell
- Weakness in your arms or legs
What are the causes?
It isn’t clear what causes a meningioma. Doctors know that something alters some cells in your meninges to make them multiply out of control,. Whether this occurs because of genes you inherit, hormones (which may be related to the more frequent occurrence in women or other factors remains largely unknown.
How common are meningiomas?
Meningiomas are one of the most common ‘brain tumours’, aand according to the latest Cancer Research UK statistics between a quarter and a third (25-33%) of all primary brain tumours in adults is a meningioma.Typically they are usually found in middle-aged or elderly adults, with an increased incidence in females.
A meningioma can be difficult to diagnose because the tumour is often slow growing. Symptoms of a meningioma may also be subtle and mistaken for other health conditions or written off as normal signs of aging. Typically they will be detected by a Computerised tomography (CT) scan or Magnetic resonance imaging (MRI) scan. In some cases, examination of a sample of the tumor (biopsy) may be needed to rule out other types of tumors and confirm a meningioma diagnosis.
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