Abstract

Abstract Background Immunoglobulin G4 (IgG4)-related diseases are systemic fibroinflammatory disease characterized by extensive infiltration of IgG4-positive plasma cells in the affected tissue(s), with high plasma levels of IgG4. However, coronary involvement is rare. Case Summary A 70-year-old man was diagnosed with IgG4-related coronary arteritis, pancreatitis, and cholangitis during full-body contrast computed tomography (CT) examination prior to surgery for an iliac artery aneurysm. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/CT showed increased uptake of 18F-FDG in the pancreas, extrahepatic bile ducts, and proximal right coronary artery (RCA). Despite the patient being asymptomatic, the RCA showed severe stenosis. The patient was administered a conservative treatment with prednisolone, 30 mg/day, gradually tapered to 5 mg/day, for 6 months. Two years later, contrast CT showed improvement of the pancreatic and bile duct lesions; however, the steroid therapy had not improved the coronary artery lesions, and gradual progression of the lesions was observed. Percutaneous coronary intervention was performed with a cutting balloon in the RCA, and good patency was maintained for 1 year after the procedure. Discussion Steroid therapy is the first-line treatment for IgG4-related diseases; however, there may be some refractory cases. The stenotic and aneurysmal type IgG4-related coronary arteritis are life-threatening; therefore, we performed revascularization using balloon angioplasty. Determining the optimal revascularization technique for drug-refractory cases requires further investigation.