Close, but no cigar: an unfortunate case of primary angiitis of the central nervous system.

Primary angiitis of the central nervous system (PACNS) is an uncommon and misunderstood disease, where little is known regarding its immunopathogenesis and appropriate treatment. Due to the constellation of nonspecific clinical features and imaging findings, PACNS is a diagnostic conundrum for clinicians and can be very difficult to treat. Case Presentation: A 64-year-old male with a history of prostate cancer presented to the emergency department with expressive aphasia and severe headache. Previously, he was diagnosed with ischemic strokes at outside hospitals and was subsequently initiated on anticoagulation medication but was later readmitted with a new onset of nontraumatic subarachnoid hemorrhage and later was found to have ischemic changes in the right temporoparietal lobe. He was suspected to have hypercoagulability of malignancy, as he was unresponsive to a wide variety of anticoagulants and his symptoms continued to deteriorate. On presentation, the physical examination was significant for right homonymous hemianopia, with positive antinuclear antibodies and notable erythrocyte sedimentation rate. The results from the full serologic workup was negative. Subsequent imaging of the brain revealed multifocal stenoses in multiple arteries. On further examination, digital subtraction angiography was concerning for vasculopathy, and was initiated on corticosteroids and cyclophosphamide. Discussion: This is one of the first cases of PACNS in which recurrent strokes were the presenting symptom for PACNS. Vasculitis should be a considered differential in patients with recurrent ischemic strokes and failed anticoagulant therapy. It is important to rule out malignancy and infectious causes due to the wide spectrum of conditions that cause central nervous system vasculitis.