Primary angiitis of central nervous system: The story of a great masquerader.

Primary angiitis of central nervous system (PACNS) is characterized by non-caseating granulomatous angiitis restricted to CNS. The condition often masquerades as migraine, stroke, epilepsy, dementia, demyelinating disorder and CNS infection. The protean manifestations frequently lead to misdiagnoses. We present a case of a young male from rural background that remained undiagnosed for years as the possibility of PACNS was not considered. He had history suggestive of migraine-like headaches followed by seizures. Subsequently, he developed rapidly progressive dementia and two episodes of hemorrhagic strokes over a short period. The diagnosis was finally clinched by the absence of evidence of systemic vasculitis and the presence of characteristic non-caseating granuloma around vessels of duramater and cerebral parenchyma on brain biopsy. He was started on pulse therapy with intravenous cyclophosphamide and methylprednisolone. The current literature about the condition and its management is reviewed in this report.