A left lung abscess with a displaced subsegmental bronchus and anomalous pulmonary artery and vein: a case report

Since a displaced bronchus related to the left upper lobe is an uncommon anatomical anomaly, it has a risk of being accidentally resected during left upper lobe resection unless they are identified preoperatively. A case of video-assisted thoracic surgery (VATS) segmentectomy that was safely performed under preoperative identification of a displaced subsegmental bronchus and anomalous pulmonary vessels is presented.

A 48-year-old woman visited our hospital because of an abnormal shadow on a radiograph on a health check. The chest computed tomography (CT) showed a multicystic mass with a diameter of 35 mm on dorsal interlobar parenchyma between the S¹⁺² and S⁶ segments in the left lung. The three-dimensional (3D) CT with multiplanar reconstruction showed that B¹⁺²b+c passed to the dorsal side of the left main pulmonary artery (PA), which was considered a displaced bronchus. The branch of A⁶ arose from the left main PA at the level of the branches of A³ and A¹⁺², more proximal than the normal anatomy, and passed to the dorsal side of a displaced B¹⁺²b+c. The branch of V¹⁺² passed between B⁶ and the bronchus to the basal segment and joined V⁶ at the dorsal side of the pulmonary hilum. Intraoperative findings of the anatomy of the bronchi and pulmonary vessels were exactly the same as the preoperative 3D CT findings, so segmentectomy of S¹⁺²b+c and S⁶ by VATS was performed safely. Then there were accessory fissures between S¹⁺² and S³ and between S⁶ and the basal segment. The pathological diagnosis was a left lung abscess.

A preoperative 3D CT may be helpful for identifying anatomical anomalies. An anatomical anomaly should be suspected if accessory fissure is found during surgery.