The pontine tumors have a poorer prognosis than the less common midbrain and medullary gliomas. Incidence Brain stem tumors account for 10 percent of pediatric brain tumors. The peak incidence is between ages five and 10. Clinical Features and Symptoms Pontine brain stem tumors affect the cranial nerves, causing symptoms related to the nerves that supply the muscles of the eye and face, and muscles involved in swallowing. These symptoms include double vision, inability to close the eyelids completely, dropping of one side of the face, and difficulty chewing and swallowing.
Tumors arising in the midbrain usually affect only the nerves supplying the eye muscles.
They also block the flow of cerebrospinal fluid in the brain, causing headaches and vomiting. Tumors involving the medulla usually cause swallowing problems and weakness of the arms and legs. Treatment Strategies Surgery is normally not done for these brain tumors because of their location. Radiation therapy has been the main treatment approach. The patients' symptoms often improve dramatically during or after six weeks of irradiation.