Partial anomalous pulmonary venous return through a left subaortic vein.

We present an unusual case of partial anomalous pulmonary venous return draining a subsegmental area of the left upper lobe into the superior vena cava. To our knowledge, this type of partial anomalous pulmonary venous return has not been described previously. We briefly describe embryologic considerations that we believe could help explain the origin of this rare anomaly.