Anomalous pulmonary artery from the aorta associated with intrapulmonary cysts (intralobar sequestration of lung); its roentgenologic recognition and clinical significance.

Abstract

This discussion is concerned with the roentgen diagnosis of an anomalous systemic artery to the lung associated with congenital cystic pulmonary abnormalities. Seven cases proved by surgical resection and subsequent pathologic examination form the basis of the study. Although there are numerous reports in the literature by surgeons who have encountered anomalous arteries arising from either the thoracic or abdominal portions of the aorta and entering the lower lobes (1, 3, 4, 5, 7, 8, 11, 13, 16, 17, 18), very little reference has been made to the preoperative diagnosis, and particularly to the roentgen findings in these cases. Because a number of deaths have resulted from inadvertent section of such an artery during lobectomy or pneumonectomy (14), the vital importance of recognition of the condition prior to surgery is emphasized. The artery is “pulmonary” in type histologically, being elastic rather than muscular (19, 20) and is frequently athero-sclerotic (2, 8, 19). It may supply only normally connected lung, only sequestered lung, or both; it usually anastomoses with normal pulmonary arteries (6). In intralobar sequestration, venous drainage is to the normal pulmonary venous system; in extralobar sequestration, drainage is to systemic veins. The pulmonary abnormality, sequestration of lung, consists in the presence of lung tissue which does not connect with the bronchial tree in the usual fashion. Lung so sequestered may lie within the lower lobe (intralobar) (19) or adjacent to the lower lobe (extralobar) (10, 12, 19), forming an accessory lobe or lung. The cases presented here are all of the intralobar type. The extralobar type will not be discussed. The sequestered portion of the lung may be composed chiefly of normally differentiated lung, a system of branching bronchi, one or more bronchogenic cysts, or a polycystic mass. The fact that such cysts sometimes contain air suggests the probability of communication with the bronchial tree, although no communication was demonstrated in the cases presented. The embryologie events responsible for the anomalous distribution of the arteries and the accompanying deformity of the lung, as well as the frequent association of hiatus hernia, have been the subject of discussion by many authors, notably Cockayne and Gladstone (9) and Pryce (19). It has been the opinion of most writers that the condition is of congenital origin. Although it cannot be disproved in any case that the cyst or cysts have been acquired, this possibility is believed to be remote (15). In all of the cases presented, the pulmonary abnormality consisted essentially of bronchogenic cyst formation within a lower lobe. In none was there demonstration of any direct communication between abnormal lung and the bronchial tree of the involved lobe. In all instances the vascular anomaly consisted of a pulmonary artery arising from the thoracic aorta or from below the diaphragm.