The Anatomy of a Novel Malformation of the Cardinal Vein System

Abstract

Anomalies of the cardinal vein system (CVS) are uncommon but if unidentified can lead to life-threatening complications. We report a case with a novel malformation of the CVS. Autopsy with in situ dissection of heart and large vessels in a 25-day-old infant was performed. The infant was diagnosed with congenital heart disease, and systemic venous malformations were suspected by imaging. Correlation between premortem imaging and postmortem anatomy was performed. The superior and inferior left venous systems developed abnormally. A persistent left superior vena cava (PLSVC) drained into the right atrium via the coronary sinus. A persistent left inferior vena cava (PLIVC) continued with the hemiazygos vein (HV), which drained into the PLSVC. The innominate vein was absent. The left renal vein was connected to the HV. Two common iliac veins were identified. The left drained into the PLIVC and the right into the right inferior vena cava (IVC). Perinatal echocardiography identified only the dilated HV draining to an LSVC and a small IVC. Congenital heart disease included hypoplastic left ventricle with hypoplastic aortic arch and subaortic stenosis, which were diagnosed by fetal ultrasound. Remodeling of components of CVS takes place during development, and unknown mechanisms guide this process. Defects of this process can lead to variable malformations, as demonstrated by this case. To our knowledge, the combination of complex malformations of both superior and IVC systems that extends to the common iliac veins has not been reported. We recommend identifying vascular anomalies in situ during autopsy before anatomic relationships are altered.