Pulmonary sequestration is defined as a segment of ç separated from the tracheobronchial tree and receiving its blood supply from a systemic artery rather than a pulmonary arterial branch. Classically, it has been described in two forms: (1) intralobar sequestration (ILS), in which the sequestrated part of lung lies within normal pulmonary visceral pleura, and (2) extralobar sequestration (ELS), in which the abnormal segment of lung is completely separate and enclosed in its own pleural investment. The term sequestration was coined by Pryce in 1946 to describe a disconnected bronchopulmonary mass or cyst with an anomalous systemic artery. Since this original description, terminology has become confusing as investigator has recognized many variants of sequestration not strictly meeting the original description. The spectrum now recognized as a continuum, with normal vessels supplying abnormal lung at one end and abnormal vessels supplying normal lung at the other end. Recently, we incidentally found an asymptomatic, intralobar pulmonary sequestration during CT pneumocolon.
A 10-month-old boy was referred for tachypnea and heart murmur. An echocardiogram showed unexplained left heart dilation without evidence of an intracardiac shunt. A 64-slice computed tomographic contrast-enhanced angiography showed a large tortuous anomalous artery arising from the descending thoracic aorta and supplying the lower lobe of the left lung. The venous return into the left atrium was normal. The affected lobe had normal lung parenchyma, and its bronchial tree was connected normally with the left main bronchus. Hence, it was not a sequestrated lobe. The boy underwent surgical lobectomy of the left lower lobe and improved. Anomalous arterial supply of a lobe without sequestration of its bronchial tree is a rare pathologic entity. It also is a very rare cause of congestive heart failure in children. Computed tomographic angiography was a useful tool for evaluation of the intrathoracic anomalous vessel in this case.