Rupture of an uncommon mediastinal aneurysm resulting in spontaneous hematoma

A 61-year-old man with a 10-year history of bronchiectasis presented to our hospital with a sudden onset of chest pain, epigastric pain, and excessive sweat. Chest computed tomography (CT) showed a large mass having mixed density in the posterior mediastinum extending all the way up to the aortic arch level. Bilateral cystic bronchiectasis was found in the lower lobe. Contrast-enhanced CT revealed a massive mediastinal hematoma and an adjacent aneurysm originating from the left gastric artery (Fig. 1a, 1b). Shortly after admission, the patient’s hemoglobin level rapidly dropped from 10.3 g/dL to 8.6 g/dL. Hemodynamic instability accompanying CT findings necessitated immediate angiography