Incidence Brain stem tumors account for 10 percent of pediatric brain tumors. The peak incidence is between ages 5 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 one side of the face, and difficulty chewing and swallowing. Symptoms usually worsen rapidly because the tumor is rapidly growing.
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 increased pressure with headaches and vomiting. Tumors involving the medulla usually cause swallowing problems and weakness of the arms and legs. Surgery may be possible in the few patients where the tumor is very localized. Radiation therapy has been the main treatment approach. The patients symptoms often improve dramatically during or after 6 weeks of irradiation.