The involvement of the central nervous system (CNS) by a vasculitic process is an infrequent but serious manifestation of several systemic diseases. The neurological disturbances are most often due to cerebral ischemia; however, vascular inflammation is not the only pathogenetic factor of CNS disease in systemic vasculitis. Most often, the specific diagnosis of CNS vasculitis depends on identifying clinical or histologic evidence of target organ involvement outside the CNS. The primary angiitis of the central nervous system (PACNS) is a rare form of vasculitis limited to the central nervous system. The diagnosis of this disorder is difficult owing to its various clinical manifestations and to the poor specificity of the neurological investigations. The demonstration by cerebral angiography and/or tissue examination of an arteritic process is mandatory for establishing this diagnosis.