Document Type

Conference Proceeding

Publication Date

5-1-2026

Abstract

IgG4-related aortitis is a rare manifestation of IgG4-related disease and can closely mimic acute aortic syndromes, including intramural hematoma (IMH), on imaging. Isolated involvement of the descending thoracic aorta is particularly uncommon, and misdiagnosis may lead to unnecessary surgical or endovascular intervention. A 68-year-old man with extensive cardiovascular disease, including prior coronary artery bypass grafting, recent percutaneous coronary intervention with drug-eluting stent placement, permanent pacemaker implantation for complete heart block, and recent pulmonary embolism, presented with three days of chest pain, shortness of breath, and left lower quadrant abdominal pain. At presentation, he was receiving apixaban, aspirin, and clopidogrel. Computed tomography angiography demonstrated a new crescentic mural hypodensity along the distal descending thoracic aorta with mild periaortic fat stranding, not present on imaging one month earlier, raising concern for intramural hematoma or type B aortic dissection. Strict anti-impulse therapy was initiated, and cardiothoracic surgery was consulted. Laboratory evaluation revealed markedly elevated inflammatory markers, including an erythrocyte sedimentation rate of 85 mm/h and C-reactive protein of 279 mg/L, along with a significantly elevated serum IgG4 level of 430 mg/dL. Total IgG was mildly elevated, and broad autoimmune, vasculitic, and infectious serologic testing was otherwise negative. Repeat non-contrast and contrast-enhanced imaging at 48 hours demonstrated stability of the aortic lesion without dissection, expansion, or aneurysm formation. The combination of imaging stability, eccentric aortic wall thickening with inflammatory features, and a strongly inflammatory serologic profile favored IgG4-related aortitis over isolated IMH. High-dose systemic glucocorticoid therapy at approximately 0.6 mg/kg/day was initiated, resulting in rapid improvement in symptoms and hemodynamic stability. Given the patient’s extensive cardiovascular comorbidities and concern for steroid-related toxicity, a steroid-sparing strategy with B-cell–directed therapy using rituximab was planned. The patient was discharged in stable condition on anti-impulse therapy, a structured glucocorticoid taper, appropriate antithrombotic management, and close multidisciplinary follow-up with interval imaging. Previously reported cases of IgG4-related aortitis most commonly involve the abdominal aorta or aneurysmal disease and often require histopathologic confirmation. This case highlights isolated descending thoracic involvement presenting as a crescentic aortic wall lesion mimicking intramural hematoma, with diagnosis supported by serologic, radiographic, and clinical response to immunosuppression. Early recognition of IgG4-related aortitis is critical, as prompt medical therapy can prevent unnecessary surgical intervention and significantly alter patient outcomes.

Comments

American College of Physicians Michigan Chapter and Society of Hospital Medicine Michigan Chapter 2026 Resident and Medical Student Day, May 1, 2026, Troy, MI

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