Glioma
In this condition factsheet:
The Facts on Glioma
Each year, approximately 3,000 Canadians are diagnosed with brain tumours. A glioma is a type of malignant brain tumour. A malignant tumour is a mass of abnormal cells that is cancerous.
Tumours can develop in any part of the brain or its nerves and covering tissues. The two major types of brain tumour are primary and secondary. Primary brain tumours start in the brain. Secondary brain tumours start in another part of the body, then spread to the brain. A glioma is a primary brain tumour, accounting for 45% of cancers that begin in brain cells.
The three main types of glioma include: astrocytoma, ependymoma, and oligodendroglioma. Each of these types can be assigned a grade, either low grade or high grade, with high grade being more malignant and aggressive.
Astrocytomas are named for the cells where they originate, the astrocytes. These tumours can either show clear borders between normal brain tissue and the tumour (called focal) or no clear border (called diffuse). Focal astrocytomas are most common in children and are not often found in adults. Glioblastoma multiforme, is the most common and most aggressive astrocytoma.
Ependymomas begin in cells called ependymal cells that are found lining certain areas of the brain and spinal cord. These cells help repair damaged nerve tissue. They usually occur in children and young adults.
Oligodendrogliomas form in oligodendrocyte cells, which produce a fatty substance called myelin that protects the nerve. More common in adults, these tumours may move to other parts of the brain or spinal cord.
Causes of Glioma
The cause of primary brain tumours is unknown. Some tumours tend to be hereditary so people who inherit specific genes may be more likely to develop a brain tumour. In other cases, a person's genes may change as they grow. Environmental factors such as food, radiation, or chemicals may cause these changes to genes.
Secondary brain tumours are caused by tumours in other areas of the body spreading to the brain.
Symptoms and Complications of Glioma
A person with a brain tumour may experience various signs and symptoms of the condition. As the tumour grows, it puts pressure on the brain and its tissues. This pressure can affect the way the blood flows, as well as damage brain cells or cause swelling of the brain.
Common symptoms of a brain tumour include headaches and seizures. Other signs and symptoms, such as loss of speech or vision, are possible and depend on the location of the tumour.
Headaches may be dull and may cause a person to feel nauseated, to vomit or to have problems with their vision. The pain caused by the headache may increase as the tumour grows. It is also possible that such headaches will feel worse when a person is physically active.
A brain tumour may also cause partial or full seizures. The swelling or shrinking of a tumour may trigger this symptom.
If the tumour is located in the spinal cord, symptoms may include:
- chest pain due to a tumour located in the chest area of the spinal cord. The pain may increase when coughing, sneezing, or lying down.
- erectile dysfunction
- lack of ability to feel changes in temperature
- loss of muscle control
- loss of bowel or bladder control
- numbness or tingling
- pain in the arm, neck, back, or leg caused by tumours in the neck area of the spinal cord
- weakness in the limbs or upper body
