CNSV is a heterogeneous group of disorders that affect the vasculature within the brain, spinal cord, and leptomeninges. Perivascular and intramural inflammation seen in CNSV can present as a primary disorder (PACNS) or secondary to another disorder (secondary CNSV). Regardless of etiology, there is vascular damage, necrosis, and tissue ischemia secondary to this process. The pathophysiology of PACNS is poorly understood but it can affect small, medium, or large vessels and the clinical presentation can vary based on the affected vessel but generally includes the insidious onset of focal neurological symptoms, headache, seizure, and cognitive impairment. There is no one test that allows diagnosis of PACNS but rather the diagnosis relies on a combination of history, physical examination, serological and CSF evaluation, MRI, vessel imaging, and in some cases, histopathological evaluation. One of the major limitations in evaluating PACNS is the lack of sensitivity and specificity in the available tests and the overlap of clinical presentations with several other mimicking conditions which need to be excluded. These include several other inflammatory and infiltrative disorders as well as secondary CNSV. Secondary CNSV could be due to systemic vasculitides, connective tissue disorders, infectious disorders, and other systemic disorders that can involve the CNS vasculature. The treatment of CNSV includes immunosuppression for PACNS or treatment of the underlying condition for secondary CNSV.