Malignant Glioma

A malignant glioma is a tumor that arises from the central nervous system, brain or spinal cord, tissue directly. A large proportion of the brain is made up of supporting cells called glia or glial cells. These cells normally help to control the environment in the brain and aid neurons, the "nerve cells" to do their thing. However, these glial cells can because tumors occasionally.

There are three basic types of glial cells, astrocytes, oligodendrocytes and ependymal cells. Each can develop into types of brain cancer, referred to as astrocytomas, oligodendrogliomas and ependymomas, respectively.

Tumors of these cells, called gliomas, can range from the more benign end of the spectrum to very malignant. They are generally graded as Grades 1 through 4. Grades 1 and 2 are considered benign glioma while Grades 3 and 4 are considered malignant glioma. The malignant gliomas tend to be faster growing, more aggressive and more invasive into the surrounding brain tissue. The most malignant tumors, Grade 4 gliomas are roughly synonymous with glioblastoma multiforme, a very aggressive tumor of glial cells which has a very poor prognosis.

Treatment of brain cancer of these types vary depending on the type, location and grade. The prognosis also varies considerably as the more benign tumors may be treatable and even curable in some situations while the most malignant are frightfully hard to control.

Types of Malignant Glioma

Oligodendrogliomas: Oligodendrocytes are cells in the brain and spinal cord that insulate the long nerve fibers of neurons, the nerve cells. Tumors arising from these cells are termed oligodendrogliomas or sometimes oligodendrocytomas.

Ependymomas: Although considered glial cells, ependymal cells are different from astrocytomas and oligodendrocytes in form and location. These cells line the fluid filled spaces within the brain, the ventricles. When these cells become tumors they are termed ependymomas. Like the other types of gliomas, they can range from benign to malignant.

Mixed Glial Tumors: Some tumors can exhibit features that are both like astrocytes and oligodendrocytes and therefore are termed mixed tumors.

Glioblastoma Multiforme: Glioblastoma multiforme is a term for the most malignant and aggressive form of malignant glioma. They most commonly originate from an astrocytoma but can evolve from other gliomas such as an oligodendroglioma. They represent the most malignant end of the spectrum of glial tumors and tend to be very aggressive, infiltrative and fast growing. Generally, despite maximal medical and surgical treatment, the prognosis remains grave for these scary brain cancers, although many cutting-edge treatments are currently being researched in laboratories and clinical trials around the world.

Grading of Malignant Gliomas

Grade I: Grade 1 is the most benign end of the spectrum of brain tumors. They are generally less invasive and slower growing examples. An example of a WHO grade 1 tumor is a pilocytic astrocytoma.

Grade II: Grade 2 is still considered benign but tend to be slightly less so than Grade 1 tumors. They are sometimes referred to as benign astrocytomas or well-differentiated astrocytomas. They can also include more benign forms of oligodendrogliomas and ependymomas.

Grade III: Grade 3 tumors are considered malignant. They are sometimes referred to as malignant astrocytomas or anaplastic astrocytomas. Can also be applied to malignant oligodendrogliomas and ependymomas.

Grade IV: Grade 4 tumors are the most malignant and aggressive brain cancers. They can arise from other glial cells but most commonly they begin from astrocytomas. These very invasive and fast growing tumors are also referred to as Glioblastoma Multiforme.