APA Dictionary of Psychology

any abnormal tissue growth (see neoplasm) within the confines of the skull. Damage may occur by the destruction of healthy tissue or through increased intracranial pressure as there is little room for the tumor to grow within the skull without compressing healthy tissue and interfering with the flow of blood and nutrients into the brain. Brain tumors can occur at any age, producing initial symptoms of headache, nausea, or sudden vomiting without apparent cause. As the tumor progresses, the patient may experience disturbances of vision, hearing, and smell, loss of coordination, changes in mental status, weakness, and paralysis. Seizures sometimes are caused by a tumor. See also glioma; meningioma.