An extremely rare case report of surgery of lung cancer with the absence of azygos vein.

In thoracic surgery, we occasionally encounter vessel anomalies. We herein report an extremely rare surgical case with the absence of the azygos vein. Mediastinal vascular abnormalities are said to be rare. The etiology of vascular abnormalities of the whole body, including the chest is known gene mutations, hormone abnormalities, infection, and trauma. But, many causes have been unknown. In thoracic surgery field, there is some reports and literature about pulmonary arteriovenous malformation, pulmonary sequestration, and partial anomalous pulmonary venous return. But reports about absence of azygos vein are not much. It is considered that it is less likely to become a problem in clinical. As we discussed in the paper, it will be more interesting if the association with PLSVC reveals from more cases. A 58-year-old man was admitted to our hospital in order to undergo operation for the treatment of lung cancer. We detected absence of the azygos vein by preoperative computed tomography (CT). Furthermore, three-dimensional angiography (3D-angiography) showed that the right superior intercostal vein and hemiazygos vein in the left thoracic cavity were more developed than usual. Then, we discuss the key points during surgery and suggest the potential association between the absence of the azygos vein and a persistent left superior vena cava (PLSVC).