[Retrotracheal left pulmonary artery: case report with an embryologic and anatomic update]

The accidental discovery of a retrotracheal left pulmonary artery in a 4-month-old infant encouraged us to review the various embryologic theories concerning this very rare anomaly and perform an anatomic update in order to better define surgical treatment. Nathan underwent surgery for a bilateral inguinal hernia at the age of 4 months. The postoperative period was marked by malaise associated with dyspnoea, stridor, tachycardia and sweating. A X-ray of the thorax, oesophageal transit and angio scan presented an intertracheo-oesophageal left pulmonary artery and a reimplantation of the left pulmonary artery was successfully performed. A retrotracheal left pulmonary artery is a very rare malformation. From development of pulmonary vascularisation, three embryologic theories have been advanced to explain this anomaly. From an anatomic point of view, Landing et al. proposed in 1982 a classification system of retrotracheal left pulmonary artery. Today, current radiological techniques not only provide a precise diagnosis but also make it possible to define appropriate care for the different types of this malformation.