Using Positron Emission Tomography to Predict Intracranial Tumor Growth in Neurofibromatosis Type II Patients

Background: * Neurofibromatosis type II (NF2) is associated with tumors of the nerves, brain, and spinal cord. Most people with NF2 develop vestibular schwannomas, or tumors on the hearing and balance nerves. As they grow, vestibular schwannomas can cause hearing loss and balance problems. If they grow very large they can cause more serious problems, such as seizures, loss of eyesight, weakness, speech problems, and problems with the sense of touch. More research is needed into NF2 because researchers do not completely understand why these tumors occur or what makes them grow over time. * Currently, tumor size is measured with magnetic resonance imaging (MRI) scans. However, MRI scans cannot predict how fast a tumor will grow. By using positron emission tomography (PET) scanning, researchers hope to be able to predict sudden growth spurts of tumors associated with NF2 and develop better treatment methods for this type of cancer. Objectives: \- To use magnetic resonance imaging and positron emission tomography to better understand the growth of brain tumors in people with neurofibromatosis type II. Eligibility: \- Individuals between 18 and 50 years of age who have been diagnosed with NF2 and have at least three untreated intracranial tumors. Design: * This study requires an initial set of outpatient visits to the NIH Clinical Center that will last 7 to 10 days. * Participants will have a physical and neurological examination and blood tests at the first visit. Participants will then have the following imaging studies to examine the tumors: * MRI scans of the brain * PET scans of the brain, combined with a computed tomography (CT) scan. The PET scans will be performed on separate days. Different contrast agents will be used for both scans, so researchers will inform participants if they need to fast or follow other procedures before having the scan. * After the initial imaging studies, participants will have additional MRI scans every 6 months for 2 years to track tumor growth.