A brain tumor is a mass of cells in your brain that are not normal. There are two general groups of brain tumors:
Primary brain tumors start in brain tissue and tend to stay there. Most malignant brain tumours develop from the glial tissue, which supports the brain’s nerve cells. These tumours are known as gliomas.
- These usually arise in the largest part of the brain, the cerebrum. They can be any grade. They often cause seizures or changes in behavior.
- Oligodendrogliomas are the third most common glioma, accounting for 2-5% of all primary brain tumours and 5-18% of gliomas. They are more common in adults, particularly in people aged 40-60.
- Ependymoma is rare. It is a type of brain tumour called glioma. They start from ependymal cells. These cells line the fluid filled areas of the brain (ventricles) and the spinal cord. Their job is to repair any damaged nerve tissue. About 2 out of 100 (2%) of brain tumours are ependymomas. Most ependymomas are diagnosed in children or young adults and can occur in any part of the brain or spinal cord. In older people they tend to occur in the lower spinal cord.
Secondary brain tumors are more common. These cancers start somewhere else in the body and travel to the brain. Lung, breast, kidney, colon, and skin cancers are among the most common cancers that can spread to the brain.
The cancer cells break away from the primary tumor and travel to the brain, usually through the bloodstream, then commonly go to the part of the brain called the cerebral hemispheres or to the cerebellum. Cancer can also spread to the spine (metastatic spine tumors).
Metastatic brain tumors are five times more common than primary brain tumors (those that originate in the brain).
Metastatic brain tumors can grow rapidly, crowding or destroying nearby brain tissue. Sometimes a patient may have multiple metastatic tumors in several different areas of the brain.
