A Case of Proteinase 3 Anti-neutrophil Cytoplasmic Antibody (PR3-ANCA) Positive / IgG4-nonrelated Inflammatory Abdominal Aortic Aneurysm Using Oral Prednisolone

Abstract

An 80-year-old man presented with a 2-month history of upper abdominal pain. The serum level of IgG4 was normal range, and PR3-ANCA was elevated. Enhanced computed tomography (CT) demonstrated a supra-renal abdominal aortic aneurysm (AAA), so-called mantle sign. The maximal diameter was 45 mm. Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) revealed intensive FDG uptake in the anterior-lateral wall of AAA. After a diagnosis of inflammatory AAA, he was started on 40 mg/day of oral prednisolone instead of surgical removal. Repeat PET/CT findings after 4 weeks of treatment demonstrated regression of wall thickening and markedly decreased FDG uptake.