An autopsy of a patient with polyarteritis nodosa who developed fatal intestinal perforation accompanied by systemic multiple aneurysms and arterial thrombosis.

The patient was a 48-year-old man who had developed acute myocardial infarction 3 years earlier. He started experiencing recurrent attacks of abdominal pain 2 years earlier. One month before the presentation, he developed perforative peritonitis, which was treated with right hemicolectomy. Preoperative computed tomography revealed systemic thrombotic aneurysms and fibrinoid necrotising vasculitis was detected in the vessels of the serosa of the resected intestinal specimen. These findings led to a diagnosis of polyarteritis nodosa. Despite the start of remission induction therapy with high-dose glucocorticoid and intermittent intravenous cyclophosphamide, the effect of immunosuppressive therapy was limited. Approximately 1 month after treatment initiation, he died from small intestinal perforation. Polyarteritis nodosa often exhibits nonspecific clinical symptoms, which make an early diagnosis difficult in some cases. Although the prognosis depends on the presence of ischaemic lesions due to a ruptured aneurysm or intra-aneurysmal thrombi, it is not rare for the diagnosis to be made following acute myocardial infarction or acute abdominal pain. In young patients with iscahemic organ dysfunction without any arteriosclerotic lesions at low risk of developing cardiovascular events, early diagnosis can be made by performing a whole-body examination with a differential diagnosis of polyarteritis nodosa.