[Azygos vein aneurysm occurring simultaneously with hemoptysis]

A 64-year-old man was admitted with hemoptysis. A chest X-ray showed a well-defined round nodule at the right tracheobronchial angle. Enhanced computed tomography revealed the superior vena cava to be completely occluded while the azygos vein was also observed to have formed an aneurysm. Bronchoscopy showed the submucosal bronchial vessels at the right second carina to be markedly dilated, and thus considered them to be the likely cause of hemoptysis. Based on the above findings, we considered the following events as the most likely to have taken place: The superior vena cava was completely occluded due to the long-term placement of a pacemaker. The blood flow of head and upper limbs could not sufficiently return to the heart, but instead flowed into the azygos vein via the collateral circulation. This resulted in both the formation of the azygos vein aneurysm and an elevated venous pressure of the bronchial vein. Due to this pressure elevation, the bronchial vein and small vessels had both ruptured, thereby inducing the onset of hemoptysis.