A brainstem glioma is a tumor that occurs in the brainstem. It is most common in children and teenagers younger than 20 years of age, but they also occur in adults between the ages of 30 and 40. These tumors are fast-growing, highly aggressive and difficult to treat. The prognosis varies depending on the location of the tumor.
These tumors can occur in three parts of the brain. Some brainstem glioma tumors occur on the midbrain, which is deep in the center of the brain. Others occur on the pons, which is the section just below the midbrain. The medulla oblongata, which is found between the pons and spinal cord, is also susceptible to gliomas.
Most brainstem tumors occur on the pons. These tumors, called pontine gliomas, affect the nerves and muscles around the face. This causes problems such as double vision and can make it difficult for the patient to chew or swallow food. As the tumor grows, the patient might also experience problems walking or feel weakness in the limbs.
Depending on the location of the brainstem glioma, patients might also experience hydrocephaly, which is a condition in which cerebrospinal fluid accumulates in the brain. People who have this condition might suffer from frequent headaches, difficulty walking or maintaining their balance and an upset stomach. Patients might also complain that they cannot feel one side of their face, or half of their face might appear to droop.
Doctors diagnose brainstem glioma tumors by performing magnetic resonance imaging (MRI) examinations. These non-invasive tests allow them to look inside the brain for the presence of tumors. They might also use computed tomography (CT) scans, although these tests are often not as accurate as MRIs.
Patients who have brainstem gliomas have limited options when it comes to treatment. The tumors are located in a sensitive part of the brain and tend to spread rapidly throughout the area, so doctors are often unable to perform surgery. Radiotherapy is also a risky option, because high doses can cause permanent damage to the brainstem.
Despite the risks, radiotherapy is the preferred method of treatment, because brainstem glioma tumors generally respond more favorably to radiotherapy than chemotherapy. Some doctors also prescribe medications to control secondary symptoms. Corticosteroids reduce inflammation, and other medicines — such as dexamethasone — can control swelling.
Patients who have pontine gliomas, or tumors on the pons, do not usually live longer than a year after diagnosis. The chances of surviving a medullary or midbrain glioma are considerably higher. Patients have about a 65-90 percent chance of long-term survival when treated with radiation therapy.