No abstract

A more difficult problem is raised by the presence, in our case, of an oesophageal diverticulum forming an aesophagobronchial fistula in the sequestered segment. The whole oesophagus is lined by ciliated columnar epithelium in early embryonic life; and the normal bronchial tree arises as an outgrowth from the foregut. Baar and d' Abreu's (1949) case of' a cyst in the esophageal wall lined by ciliated epithelium must be considered as a variety of duplication of the foregut. The diverticulum we describe may also be regarded as a duplication of the foregut. T o account for its communication with the cystic pulmonary mass there appear to be two possibilities. Firstly, it may have 'captured' the terminal bud (destined to form the posterior basal segment) of the developing bronchus, which has then lost its normal attachment and acquired a new one. Secondly, the diverticulum may have acquired the potentialities, as well as the structure, of a developing bronchus, and itself differentiated into a mass of pulmonary tissue. In this case one would have to suppose that the differentiation of the normal posterior basal s e m e n t from the terminal stem bronchus had been competitively inhibited by MULTIPLE the abnormal 'bronchus'. SUlCllMARYA case of intralobar sequestration of the lung, associated with an oesophageal diverticulum (aesophagobronchial fistula) and an aberrant 'elastic' artery, is described. It is considered that the malformation is probably a variety of duplication of the foregut.