My brother has developed glioma. What is it exactly?

Primary brain tumor. Glioma is a tumor that originates from the brain cells themselves. This is in distinction to tumors (cancer) that spread to the brain from somewhere else, or some benign tumors that occur on certain nerves or grow on the covering of the brain (meningioma). Gliomas are usually treated by a combination of surgery, radiation, and sometimes chemotherapy.
Nerve cell disorder. Glioma refeers to an abnormal collection of glial cells or nerve cells. There are several different types of gliomas. Some are benign, others are extremely malignant such as gbm, what senator kenedy had.