Hypogenetic Right Lung with Partial Anomalous Pulmonary Venous Return (PAPVR) Without the Typical Features of "Scimitar" Sign.

The partial anomalous pulmonary venous return (PAPVR) aka partial anomalous pulmonary venous connection (PAPVC), is a rare congenital cardiovascular condition in which some of the pulmonary veins, drain into the systemic circulation (Halasz, 1956). While congenital, there is no known cause was attributed for these conditions and may possibly be multifactorial in origin. Scimitar syndrome, first described by Raoul Chassinat in 1836, is a variant of the PAPVR and PAPVC characterized by an abnormal pulmonary venous return of the right lung into the inferior vena cava or right atrium via the superior vena cava (SVC), thus a left-to-right shunt. Hypoplasia of the pulmonary arteries and abnormal bronchial branching accompany this syndrome and the abnormal venous drainage involves the right side. This report is based on the cadaveric dissection of a 71-year old Caucasian male donor who died of chronic obstructive pulmonary disease/hypertension. We noted a faint incisional scar on the thorax, there was an incision extending from the parasternal region at the 4 intercostal level to the midaxillary line. Considering the straight-line incision followed the ribs and the faintness of the scar was faint, we believe the surgery was done when the donor was young. We also observed numerous surgical interventions of the heart, lungs and vasculature to correct various defects. The morphology of the heart was normal, but was shifted more to the right side. An atrial septal defect (ASD) was closed with sutures. The right superior pulmonary vein that drained into the SVC was ligated close to the SVC. We noticed a dilated coronary sinus entering the right atrium adjacent to the ASD and the ostium of the coronary sinus noticeably lacked the normal valve like structure. We initially thought the right lung was a "horseshoe" lung but realized that it was a "hypogenetic" lung with PAPVR and an accessory diaphragm. The right secondary bronchi were much narrower compared to the left and branched uncharacteristically as seen in hypogenetic lung syndrome. The inferior lobe was highly disorganized, severely hypoplastic and exhibited uncharacteristic morphology. The superior bronchopulmonary segment was markedly hypoplastic. The medial basal segment was not only hypoplastic and slender but extended like a tail to the left pulmonary cavity behind the heart/pericardium and in front of esophagus and aorta. The right lung though hypoplastic, demonstrated patent bronchi and the lobes were inflatable. The superior pulmonary vein from the right upper and middle lobes drained directly into the SVC and the inferior right pulmonary vein from the lower lobe drained into the left atrium. The left superior and inferior pulmonary veins drain directly into the left atrium. The poster will illustrate numerous images as described in our results, discuss the embryology of pulmonary veins, hypogenetic lung, "scimitar" syndrome and accessory diaphragm. To sustain life, all the defects were corrected in childhood which allowed the donor to live for 71 years.