Airway obstruction by an aortic false aneurysm.

Aortic false aneurysms are rare complications of aortic valve replacement and cardiac surgical procedures in general. Aortic false aneurysms can also presents as a mediastinal mass. A false aneurysm etiology should always be considered in mediastinal mass exploration of patients with a cardiac surgery history. Although, a computed tomography (CT) scan can detect a mediastinal mass, it can equally misdiagnose an aneurysm in the absence of tumour contrast enhancement. We present the case of a 60-year-old woman who was hospitalized for a laryngeal dyspnea. She had undergone aortic valve replacement 3 years earlier and had no other relevant medical history. In the last 3 months, she presented a progressively worsening dyspnea and cough. A chest radiograph showed a large mass in the superior mediastinum. A contrast-enhanced CT-scan showed an anterior mediastinal mass (9 cm × 8 cm × 9 cm) not enhanced by contrast product, suggestive of a tissue density tumour. The mass was in fact an aortic false aneurysm where the communication with the aorta was too narrow to be filled by the contrast product in arterial phase imaging. The aneurysm was excised and successfully replaced with a prosthetic graft during deep hypothermic and circulatory arrest. In this case report, we discuss the unusual clinical presentation of this pseudoaneurysm and the absence of contrast enhancement during CT-scan, which could have lead to a catastrophic error.