Stereotactic radiosurgery using the gamma unit has been used to manage patients with brain stem tumors or vascular malformations as an alternative to microsurgical resection. Whether associated with the pial or ependymal brain stem surface or within the brain stem parenchyma proper, radiosurgery provides relatively safe and effective management. Radiosurgery is a valuable alternative for many patients with pathologic lesions of the brain stem and may represent the only surgical option for some patients.