Brain tumour

Brain tumour - An abnormal growth in or on the brain. Tumours may be primary growths arising directly from tissues within the skull or metastases (secondary growths) that have spread from tumours elsewhere in the body.

The cause of primary brain tumours is not known. About 60 per cent are gliomas (frequently cancerous), which arise from the brain tissue. Other primary tumours include meningiomas, acoustic neuromas, and pituitary tumours. Most of these tumours are noncancerous, but their size can cause local damage. Certain types of primary brain tumour mainly affect children. These include 2 types of glioma called medulloblastoma and cerebellar astrocytoma.

Primary brain tumours virtually never spread (metastasize) outside the central nervous system. Symptoms include muscle weakness, loss of vision, or other sensory disturbances, speech difficulties, and epileptic seizures. Increased pressure within the skull can cause headache, visual disturbances, vomiting, and impaired mental functioning. Hydrocephalus may occur. When possible, primary tumours are removed by surgery after opening the skull (see craniotomy).

In cases where a tumour cannot be completely removed, as much as possible of it will be cut away to relieve pressure. For primary and secondary tumours, radiotherapy or anticancer drugs may also be given. Corticosteroid drugs are often prescribed temporarily to reduce the size of a tumour and associated brain swelling.