Abnormal branch of right pulmonary artery (A7): a case report and literature review.

In thoracic surgery, anatomic variations of pulmonary artery increase the risks for vessel injury and critical mistakes during pulmonary artery resection. We report a case of lung cancer with an extremely rare branch, a mediastinal A7 pulmonary artery. Some case reports of the mediastinal pulmonary artery exist until now. However, to the best of our knowledge, this is the first case of a medial basal segmental artery (from the following, it is referred to as A7) branching directly from main pulmonary artery in the literature. Therefore, there is no report that showed three-dimensional computed tomography (3D-CT) and operative findings. So, these information is very useful for thoracic surgeon. A 67-year-old man was admitted to our hospital in order to undergo operation for the treatment of lung cancer. We detected the anomalies preoperatively by 3D-CT. The 3D-CT shows the A7 pulmonary artery branches from the right main pulmonary artery directly. According to previous literature, the cases of a single branch from main pulmonary artery to lower lobe are only five cases. And, the only two of them are right side including our case. In spite of an extremely rare case, we were able to successfully perform a right middle lobectomy because the information obtained from the 3D-CT findings was sufficiently understood preoperatively.