Progress has been made in the pathological classification of vasculitis. The group of diseases previously diagnosed as polyarteritis nodosa (PAN) has been expanded to include other vasculitides, mainly microscopic polyangiitis. At the Chapel Hill Consensus Conference (CHCC) in 2012, PAN was defined as “necrotizing vasculitis of medium and small arteries, without glomerulonephritis or vasculitis of small arteries, capillaries, and venules, and not associated with antineutrophil cytoplasmic antibodies (ANCA)” [1]. The most common sites affected by PAN are the skin, joints, kidneys, gastrointestinal tract, and peripheral nerves [2,3]. Central nervous system (CNS) involvement in PAN has been reported in 15%–40% of cases, usually occurring several years after diagnosis [4]. Although rare, some cases in which CNS symptoms due to PAN are the initial manifestation have been reported [4], [5], [6]. However, the etiology of PAN has not yet been established.

Here, we present an autopsy case of a 28-year-old male who died suddenly due to subarachnoid hemorrhage (SAH) caused by inflammatory pseudoaneurysm rupture in the subarachnoid cerebral artery, which was associated with PAN.