Ductus arteriosus aneurysm with left pulmonary artery obstruction.

The echogenic mass in the pulmonary artery is a rare finding in newborns. Differential diagnoses include pulmonary artery thrombosis, ductal aneurysm, and malignant tumor. We report a newborn case who presented with mild desaturation and was found to have a large echogenic mass at the pulmonary bifurcation on echocardiography, which caused partial flow obstruction in the proximal left pulmonary artery. Along with the findings of cardiac computed tomography and magnetic resonance imaging, the diagnosis of ductus arteriosus aneurysm (DAA) was made. This DAA spontaneously regressed without any intervention at 4 months follow-up.