A rare case of unilateral agenesis of left pulmonary artery presenting as severe pulmonary arterial hypertension.

A 26-year-old young male patient presented with progressive dyspnea over the previous 2 years. The patient also had pulmonary hypertension. Computed tomography (CT) pulmonary angiography showed absence of the left pulmonary artery, and conventional pulmonary and aortic root angiograms showed ipsilateral lung receiving collaterals from the left internal mammary artery and thyrocervical trunk.