Extralobar sequestration with unusual arterial supply and venous drainage.

We present a case of extralobar pulmonary sequestration between the left lower lobe and diaphragm with an unusual arterial blood supply and venous drainage. Angiography revealed a large systemic artery arising from the left subclavian artery. The venous return paralleled this anomalous artery and drained into the left subclavian vein. This case illustrates the wide anatomic variability of such complex bronchovascular anomalies. Careful preoperative evaluation of both the arterial supply and venous drainage is important to avoid intraoperative complications. Angiography provides clear definition of these abnormal vascular structures, which is essential for appropriate therapeutic management.