Figure 1. A 5-week-old female infant with left lower lobe extralobar sequestration. (a) Enhanced axial CT image demonstrates heterogeneously enhancing, solid mass located within the left lower thorax (S). Also noted is an anomalous vessel anterior to the mass (short arrows), which 3D volume-rendered images identified as an anomalous vein draining into the left internal mammary vein. Enlarged left internal mammary vein is also seen (long arrow). (b) Enhanced axial CT image shows a small vessel (long arrow) adjacent to the descending aorta (short arrow) and coursing toward left lower thoracic mass (S), most likely representing anomalous arterial vessel supplying extralobar sequestration. The entire course of the vessel could not be obtained on axial CT images alone. Again noted is anomalous draining vein (arrowhead). (c) Sagittal 3D volume-rendered image demonstrates entire course of anomalous vein (short arrows) from extralobar sequestration (S), coursing anteriorly toward the heart and draining into left internal mammary vein. Anomalous artery (long arrow) arising from descending aorta is also well visualized.