RESUMO
Although renal aneurysmal formation in polyarteritis nodosa is common, it is rare to form complication of perirenal hematoma caused by spontaneous rupture of renal aneurysm. It should be differentiated from renal tumor, arterio-venous malforrnation, renal infarction, coagulopathy, and acute hydronephrosis in considering the cause of perirenal hematoma. In addition to that, it is a potential life-threatening complication and its early recognition and prompt treatrnent are emphasized. We describe a patient with polyarteritis nodosa who developed spontaneous perinenal hematoma due to repture of renal aneurysm, who had nonspecific symptoms. We thought polyarteritis nodosa based on present illness and clinical background, then immediately performed angiography and coil embolization. So the patient could be treated with cyclophosphamide and steroid successfully. Polyarteritis nodosa is a relatively rare disease, but should be included as one of the differential diagnosis whenever perirenal hematoma occurs.