IgG4-related aortitis mimicking acute aortic and coronary syndromes, multimodality imaging-pathology correlation: a...

IgG4-related aortitis is an uncommon inflammatory condition that can closely mimic both acute aortic and coronary syndromes, posing a major diagnostic challenge in patients presenting with chest pain.

A 64-year-old man with prior non-ST-elevation myocardial infarction (NSTEMI) and persistent angina presented with abrupt-onset, severe retrosternal chest pain and dynamic lateral ST-segment depression. Rising high-sensitivity troponin supported a working diagnosis of high-risk NSTEMI. During observation, he developed acute respiratory failure and hemodynamic collapse. Echocardiography revealed a large circumferential pericardial effusion with reduced left ventricular ejection fraction, without classic tamponade physiology. Contrast-enhanced computed tomography demonstrated a crescentic ascending aortic wall thickening consistent with Stanford type A intramural hematoma extending into the arch vessels. A pericardial window drained 550 mL of serohemorrhagic fluid, with transient improvement, but recurrent instability prompted emergent ascending aortic replacement and coronary bypass grafting. Despite maximal support, the patient died intraoperatively. Histopathological analysis revealed dense lymphoplasmacytic infiltration rich in IgG4-positive plasma cells and storiform fibrosis, confirming IgG4-related aortitis.

This case highlights the ability of IgG4-related aortitis to mimic both intramural hematoma and acute coronary syndromes, illustrating a critical diagnostic blind spot in acute cardiovascular care, particularly when imaging findings, clinical presentation, and intraoperative observations are discordant.