Definitive diagnoses in neuro-oncology often require invasive procedures, such as surgical biopsies to obtain tissue for histopathologic and molecular interrogation. Patients with small lesions that may respond to nonsurgical treatments, such as chemoradiation, may nevertheless undergo surgery with potential risks to obtain diagnostic tissue. A means for noninvasively obtaining diagnostic information from brain tumors may improve patient care by limiting the need for surgery. Molecular evaluation of exosomes may provide such a means. Exosomes are small vesicles excreted from tumor cells that contain molecular information. Isolation of these vesicles from peripheral fluids, such as blood and urine, may provide diagnostic information for rendering a definitive diagnosis. Here, we review current clinical data for exosome-mediated brain tumor diagnostics.