These tumours grow from the meninges, the layers of tissue covering the brain and spinal cord. As they grow, meningiomas compress adjacent brain tissue. Symptoms are often related to this compression of brain tissue, which can also affect cranial nerves and blood vessels. In some cases, meningioma growth can also extend into the bones of the head and face, which may produce visible changes. Most meningiomas are considered non-malignant or low grade tumours. However, unlike non-malignant tumours elsewhere in the body, some of these brain tumours can cause disability and may sometimes be life threatening. In many cases, meningiomas grow slowly. Other meningiomas grow more rapidly or have sudden growth spurts. There is no way to predict the rate of growth of a meningioma or to know for certain how long a specific tumour was growing before diagnosis. Meningiomas are graded from low to high. The lower the grade, the lower the risk of recurrence and aggressive growth.
The WHO classification divides meningiomas into three grades:
- Grade 1: Benign Meningioma
- Grade 11: Atypical Meningioma
- Grade 111: Malignant (Anaplastic) Meningioma
Characteristics
- May arise after previous treatment from ionizing radiation or excessive x-ray exposure
- Common among women and men in their 40s-50s, but can occur at any age
- Twice as common in women as in men
- Accounts for 34 percent of all primary brain tumours
- In very rare cases, can invade the skull or metastasize to the skin or lungs
- Women with meningiomas can experience tumour growth during pregnancy
- In rare cases, multiple meningiomas can develop at the same time in different parts of the brain and/or spinal cord
Symptoms
- Seizures
- Headaches
- Nausea and vomiting
- Vision changes
- Behaviour and cognitive changes
- Sometimes no symptoms occur and tumour is detected accidently
Treatment
If there are no symptoms, the doctor may monitor the tumour with MRIs. Otherwise surgery is the standard treatment. If the tumour cannot be completely resected or if it recurs, radiation therapy may be given as well. Chemotherapy for unresectable, aggressive, atypical, or recurrent meningiomas is being tested through clinical trials. Follow-up scans are needed indefinitely, because meningiomas can recur years or even decades after treatment.
