Aberrant mediastinal mediobasal segmental pulmonary artery in a patient with lung cancer undergoing right lower lobectomy: a case report

BACKGROUND: A mediastinal mediobasal segmental pulmonary artery (A7) from the right main pulmonary artery is extremely rare. CASE PRESENTATION: We report the case of a 71-year-old woman with an aberrant mediastinal A7 who underwent right lower lobectomy for lung cancer (cT1bN0M0, stage IA2). Preoperative three-dimensional computed tomography (CT) angiography revealed an aberrant mediastinal A7 in the right main pulmonary artery. Right lower lobectomy and mediastinal lymph node dissection were performed. Intraoperatively, A7 was observed between the superior and inferior pulmonary veins and in the front of the lower bronchus near the anterior hilum. The artery was carefully dissected from the caudal side after inferior pulmonary vein dissection. The lung parenchyma, which was within the fissure due to poor lobulation between the middle and lower lobes, was safely divided. CONCLUSIONS: Thoracic surgeons need to carefully evaluate CT angiography or enhanced multidetector CT findings at preoperative conferences and always keep this anomaly in mind.