Malignant gliomas constitute 65% of all primary brain tumors. There are three types
- Astrocytoma - affects cells of the tissue that supports nerve cells (glial cells). These can be benign or malignant and occur in both children and adults.
- Ogliodendroglioma - affects cells that form the myelin sheath around nerve fibers in the brain (oligodendrocytes). The are usually benign but can become malignant. They also occur in children and adults.
- Glioblastomamultiforme - affects less differentiated forms of glial cells and oligodendrocytes. GBM is usually malignant and occurs in adults. Gamma Knife radiosurgery may be used as a means to palliate the progression of malignant gliomas. It is generally felt that radiosurgery may be useful in achieving control of small lesions that have not progressed in a diffuse fashion.
The majority of patients with malignant gliomas, however, tend to have diffuse infiltration of the brain with poorly demarcated boundaries and do not benefit from stereotactic radiosurgery.