Coronary Arteritis in Indolent IgG4 Disease.

A 68-year-old man with a history of abdominal aortic aneurysm presented with incidental coronary artery thickening on coronary CT angiography (CCTA). Eight years later, increased thickening was noted on CCTA and cardiac MRI, with PET/CT showing FDG avidity. Serology revealed elevated IgG4 and ESR. High-dose prednisone led to decreased wall thickening and FDG avidity; rituximab was initiated following relapse. This case highlights the challenges of diagnosing IgG4-related coronary arteritis and underscores the essential role of advanced imaging in guiding surveillance and therapy, especially in asymptomatic patients.