Improvement of Mass Lesions around Coronary Arteries and Fractional Flow Reserve after Steroid Therapy in Immunoglobulin-G4-related Coronary Periarteritis

Immunoglobulin-G4-related disease (IgG4-RD) is a multi-organ systemic inflammatory disorder. The ideal treatment of coronary artery involvement in IgG4-RD remains uncertain due to its rarity. We herein report a case of coronary artery involvement with IgG4-RD, wherein mass lesions surrounded the coronary arteries with a moderate stenosis lesion in the right coronary artery (RCA). The fractional flow reserve (FFR) of the RCA was 0.76. After steroid therapy, the mass lesions around the coronary arteries improved. The FFR of the RCA also improved from 0.76 to 0.86. These findings suggest the efficacy of using steroid therapy for coronary artery involvement with IgG4-RD.