Mediastinal A5: a novel artery variant of the pulmonary artery system: a case report

Background Variations in the pulmonary artery require increased attention from thoracic surgeons prior to or during lobectomy to avoid severe intraoperative bleeding. Patients with pleural and/or hilar adhesions typically experience more intraoperative bleeding and need longer surgical time. Neglect of the variant pulmonary arteries in the context of strong adhesions may result a fatal bleeding, especially in patients with adhesions caused by pulmonary tuberculosis. Case presentation A 52-year-old man who presented with tuberculoma and strong hilar adhesions of the right upper lobe underwent tri-portal video-assisted thoracoscopic(VATS) lobectomy in our department. In this case, we identified a variant pulmonary artery (mediastinal A5) through three-dimensional computed tomography bronchography and angiography(3D-CTBA). It was an artery that originated from the proximal pulmonary artery trunk, and coursed between the branches of central vein and V1 + 3. The precise identification of this mediastinal A5 artery ensured a safe surgery procedure (Right upper lobectomy) without severe intraoperative bleeding. It is the first report that illustrated a variant mediastinal A5. Misdiagnosis of this variant pulmonary artery may result in severe intraoperative bleeding. 3D-CTBA which could illustrate the variant pulmonary arteries is essential in planning the surgical procedures. Conclusion 3D-CTBA can help illustrating a variant pulmonary artery, and identification of the mediastinal A5 is essential in preforming right upper lobectomy.