Gliomas represent a family of tumors that arise from the supporting cells of the nervous system that surround the actual nerve fibers or neurons. The most common variety, the astrocytomas, can occur throughout the nervous system from the cerebral hemispheres to the spinal cord. Those in adults most commonly occur in the cerebrum while those in the pediatric population more commonly involve the posterior fossa structures, the cerebellum and brainstem. Astrocytomas are classified according to the degree of malignancy as seen on pathologic examination, the higher grades (Grades III and IV also referred to Anaplastic Astrocytoma and Glioblastoma Multiforme respectively) have a worse prognosis. The lower grade tumors (Grades I and II) have a more benign behavior although some may transform (malignant degeneration), over time, into more malignant tumors.
Treatment depends upon the location of the tumor, size of the lesion, symptoms and general health of the patient. In some cases surgical removal would be associated with unacceptable complications, such as the inability to speak or paralysis of an extremity. In these situations biopsy for achieving a diagnosis is the treatment of choice. Often surgical excision is possible and recommended since prognosis can be improved, with some gliomas, if the majority of the tumor cells are removed. Tumors with more malignant features in most cases require radiation treatment and chemotherapy in combination with surgery. The more benign tumors often can be followed with periodic MRI scans and do not necessarily require chemotherapy or radiation treatment.