A case report of abnormal branching of left A8+9 pulmonary artery

A 75-year-old man underwent left lower lobectomy via video-assisted thoracic surgery because of clinical T1N0M0 primary lung cancer. He showed abnormal branching of the left A8+9, which branched from the left main pulmonary artery and descended between the left upper pulmonary vein and left upper bronchus. We mistook it as a mediastinal type of A4+5 and cut it after ligation. However, we noticed the error after interlobar dissection and reconstructed the distal A8+9 stump to the A4+5 stump by end-to-side anastomosis, without conversion to an open thoracotomy. This is the third case report of abnormal branching of the basal pulmonary artery, which branched from the left main pulmonary artery, in Japan.