Abstract
A 49-year-old Japanese man received a diagnosis of immunoglobulin G4-related coronary arteritis (IgG4-RCA), discovered following the detection of abdominal aorta wall thickening on computed tomography (CT). Intravascular ultrasonography (IVUS) revealed thickening of both the adventitia and the intima-media complex (IMC) in the left anterior descending (LAD) coronary artery, without significant stenosis. Corticosterone therapy was administered. On the fifth day of corticosterone therapy, the patient experienced an acute coronary syndrome secondary to LAD artery ostium occlusion, and a primary percutaneous coronary intervention was performed. After 3 months of corticosterone therapy, IVUS follow-up showed a decrease in the adventitia and IMC thickening. After 9 months of corticosterone therapy, positron emission tomography combined with CT revealed that the abnormal accumulation of fluorodeoxyglucose in the coronary arteries and abdominal aorta had disappeared. Considering the treatment process and the existing literature, there is a possibility that the adventitia and IMC deformation was induced by IgG4-RCA.