Left upper lobectomy for lung cancer with a subaortic anomalous left brachiocephalic vein: a case report

A subaortic anomalous left brachiocephalic (innominate) vein is a rare systemic venous anomaly. Although usually asymptomatic, when it traverses the aortopulmonary window it may obscure the operative field and increase the risk of vascular injury during left upper mediastinal procedures, including station 4 L lymph node dissection and exposure or control of the left pulmonary artery.

A man in his seventies presented with a 4.2-cm solid mass in the left upper lobe (S3b) and an enlarged station 4L lymph node. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of station 4L demonstrated carcinoma consistent with non-small cell lung cancer (NSCLC). Given resectable single-station N2 disease and pre-existing interstitial lung disease with a usual interstitial pneumonia (UIP) pattern, a surgery-first strategy was selected. Preoperative contrast-enhanced computed tomography (CT) with three-dimensional reconstruction demonstrated an anomalous left brachiocephalic vein coursing along the left lateral side of the aortic arch and then beneath the aortic arch, superior to the left pulmonary artery, and crossing the aortopulmonary window before draining into the superior vena cava (Takada pattern b/c). Video-assisted thoracoscopic left upper lobectomy with systematic mediastinal lymph node dissection was performed. Early identification of the left vagus nerve enabled safe proximal tracing to the left recurrent laryngeal nerve. En bloc dissection of the station 4L and station 5 lymph node regions and left pulmonary artery management were completed without neural or vascular injury. The ductus arteriosus ligament (DL) could not be identified intraoperatively, suggesting a retroductal course (Takada pattern c).

Preoperative identification of a subaortic anomalous left brachiocephalic vein on contrast-enhanced computed tomography (CT) with three-dimensional (3D) reconstruction, together with early identification of the vagus and recurrent laryngeal nerves and careful pulmonary artery management after establishing a safe dissection plane, may facilitate safe dissection in the aortopulmonary window and help prevent neural or vascular injury.