Polyarteritis nodosa with perirenal hematoma due to the rupture of a renal artery aneurysm.

We present the case of a 67-year-old man in good health with perirenal hematoma due to a ruptured arterial aneurysm in the kidney. The patient developed weight loss, muscle weakness, multiple mononeuropathy, hypertension, anemia, renal insufficiency, and multiple lacuna infarctions about a month ago. He was admitted to the hospital due to worsening of his symptom. After admission, severe right-flank pain suddenly occurred; he was then transferred to our hospital. Renal angiography revealed bilateral multiple microaneurysms, and the patient was diagnosed with polyarteritis nodosa based on the clinical, radiographic, and histological findings. We performed selective coil embolization to the ruptured aneurysm and administered oral prednisolone along with intravenous methylprednisolone pulse therapy. Cyclophosphamide pulse therapy was also given. The treatment improved clinical and laboratory findings and achieved clinical remission. Selective coil embolization to the bleeding aneurysm of polyarteritis nodosa was minimally invasive and promptly effective. Immunosuppressants proved useful in the regulation of disease activity and the aneurysm.