Feasibility of Intraoperative Microdialysis During Neurosurgery for Central Nervous System Malignancies

Who May Qualify: - Age \>= 18 years - Diagnosis of the following, based on clinical and radiographic evidence: - Any glioma - Metastatic brain tumor of any primary origin - Epileptic focus requiring surgical resection - Planned neurosurgical procedure for purposes of biopsy or resection of suspected or previously diagnosed brain tumor (primary or metastatic) or epileptic focus as part of routine clinical care - Willing to undergo neurosurgical resection or biopsy at Mayo Clinic (Rochester, Minnesota \[MN\]) - Ability to understand and the willingness to sign a written willing to sign a consent form document Who Should NOT Join This Trial: - Vulnerable populations: pregnant women, prisoners or the mentally handicapped - Patients who are not appropriate candidates for surgery due to current or past medical history or uncontrolled concurrent illness Always talk to your doctor about whether this trial is right for you.