Truncus arteriosus (TA) is a rare congenital cardiovascular anomaly characterized by a single arterial trunk arising from the heart by means of a single semilunar valve (<I>i.e.</I> truncal valve). Pulmonary arteries originate from the common arterial trunk distal to the coronary arteries and proximal to the first brachiocephalic branch of the aortic arch. TA typically overrides a large outlet ventricular septal defect (VSD). The intracardiac anatomy usually displays situs solitus and atrioventricular (AV) concordance.

A vascular malformation resulting from a developmental error of venous tissue composed of dysmorphic channels lined by flattened endothelium and exhibiting slow turnover. A venous malformation may present as a blue patch on the skin ranging to a soft blue mass. Venous malformations are easily compressible and usually swell in thewhen venous pressure increases (e.g., when held in a dependent position or when a child cries). They may be relatively localized or quite extensive within an anatomic region.