Definition of Brain stem glioma

Brain stem glioma: A malignant tumor that arises in the brain stem, the part of the brain that connects to the spinal cord. The brain stem controls many vital functions. Tumors in this area generally cannot be removed. They are often resistant to treatment and carry a poor prognosis (have a dismal outlook).

Malignant gliomas are the most common primary tumors of the central nervous system (CNS). They arise in the glial, or supportive, cells of the CNS.