A Rare Case of Dissecting Superior Mesenteric Artery Aneurysm in Granulomatosis with Polyangiitis.

An asymptomatic dissecting superior mesenteric artery (SMA) aneurysm in granulomatosis with polyangiitis (GPA), historically termed Wegener's granulomatosis, is rare. We herein describe a 68-year-old man who was diagnosed with GPA based on a high level of proteinase 3 (PR3)-antineutrophil cytoplasmic antibody (ANCA). One year after remission of GPA, the patient developed pyelonephritis, and his PR3-ANCA level increased again. Computed tomography showed a rapid increase in the size of the dissecting SMA aneurysm. The patient underwent successful endovascular stent-graft repair. At the time of this writing, 3 years had passed since the surgery and the clinical course was good.