Glioma

Glioma

Glioma is a type of tumor that occurs in the brain and spinal cord. Gliomas begin in the gluey supportive cells (glial cells) that surround nerve cells and help them function. “Glioma” is a general term used to describe any tumor that arises from the supportive (“gluey”) tissue of the brain. This tissue, called “glia,” helps to keep the neurons in place and functioning well.

Three types of glial cells can produce tumors. Gliomas are classified according to the type of glial cell involved in the tumor.

There are 3 main types of glioma                                                                     

·     Astrocytoma

·     Oligodendroglioma

·     Ependymoma

An astrocyte will produce astrocytomas (including glioblastomas), an oligodendrocyte will produce oligodendrogliomas, and ependymomas come from ependymal cells. Tumors that display a mixture of these different cells are called mixed gliomas.

Astrocytomas (including glioblastoma multiforme)

Astrocytomas are the most common type of glioma in both adults and children. They develop from cells called astrocytes. The astrocytes are the cells of the brain that support the nerve cells (neurones). Astrocytomas can be slow growing (low grade) or fast growing (high grade). Some are very localised (focal). This means it is easy to see the border between the tumour and normal brain tissue on a scan or during an operation. Focal astrocytomas are more often diagnosed in children and are not common in adults

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Other astrocytomas are called diffuse. These do not have a clear boundary between the tumour and normal brain tissue.

Anaplastic astrocytoma (also called grade 3 astrocytoma) and glioblastoma multiforme (GBM or grade 4 astrocytoma) are the most common type of brain tumour in adults. These are malignant (high grade) brain gliomas. They can sometimes spread to other parts of the brain.

Oligodendroglioma

An oligodendroglioma tumor is a slow-growing brain tumor that usually occurs in young adults. These tumors are frequently located within the frontal, temporal or parietal lobes and cause seizures in a relatively high percentage of patients. Many oligodendrogliomas contain little specks of calcium (bone) and can easily bleed.

On imaging these tumour commonly present as a round or oval sharply marginated mass involving the cortex or subcortical white matter, with low attenuation on CT, hypointense compared to gray matter on T1 and hyperintense compared to gray matter on T2-weighted MRI images. The attenuation or signal can be eventually heterogeneous due calcification, cystic degeneration and hemorrhage.

Ependymomas

About 2 out of every 100 brain tumours (2%) are ependymomas. These develop from cells called ependymal cells. These cells line the fluid filled areas of the brain (the ventricles) and the spinal cord. Their job is to repair any damaged nerve tissue.

Most ependymomas are diagnosed in children or young adults and can occur in any part of the brain or spinal cord. In older patients they tend to occur in the lower part of the spinal cord. Ependymomas can be high or low grade, but the cells' appearance under a microscope does not always fit with their behaviour. So the grade may not tell you much about how likely the tumour is to grow or spread.

Sometimes ependymomas can spread to other parts of the central nervous system, through the fluid that circulates around the brain and spinal cord.

Treatment for Gliomas

The best treatment for an individual patient takes into account the tumor location, potential symptoms, and potential benefits versus risks of the different treatment options (modalities).

Treatment for a glioma is customized to the individual patient and may include surgery, radiation therapy, chemotherapy, or observation. Treatment for patients with brain tumors is best done by a multi-disciplinary team. This includes neurosurgeons, medical neuro-oncologists and radiation therapists