Main pulmonary artery trifurcation in association with persistent right common pulmonary vein: a piece of embryological puzzle

Wide variety of congenital anomalies of pulmonary arteries like pulmonary stenosis, pulmonary atresia, proximal interruption, anomalous origin of left pulmonary artery (LPA) and idiopathic dilatation of pulmonary trunk are described in the literature (1,2). Few studies have also described the variations in pulmonary artery branching pattern, mainly describing anomalies of lobar and segmental branching pattern (3,4). Combination of ipsilateral arterial and venous anomaly is relatively uncommon. We present a unique case of main pulmonary artery (MPA) trifurcation into LPA, right upper and lower lobar pulmonary arteries with associated persistent right common pulmonary vein (rCPV). We review the embryology and propose an embryological explanation to this rare anatomical variation.