No abstract

A 53-year-old man presented to a previous hospital for evaluation of a 1-month history of back pain. Contrastenhanced computed tomography revealed a 3.5-cm azygos vein aneurysm (AVA) and massive pleural effusion, suggestive of AVA rupture. The patient was referred to our hospital on the same day and underwent emergency AVA resection.A massive hematoma and bleeding from the aneurysm were confirmed in the thoracic cavity. Thoracotomy was performed because it was difficult to stop the bleeding. The patientʼs postoperative course was uneventful, and he was discharged 8 days postoperatively.AVAs are extremely rare, and indications for surgical resection remain unclear. AVAs have risks of thromboembolism and rupture. Aneurysm enlargement, saccular structure, and a history of connective tissue disease have been reported as risk factors of rupture. The saccular structure of the aneurysm might have been a risk factor in our case. In the case of AVA rupture, bleeding control is difficult; therefore, surgical resection is recommended to avoid aneurysm rupture even if there are no signs of thromboembolism or rupture.