Epithelium in tuberculous pulmonary lesions.

During the last decade the availability of surgical material has stimulated morphologic observations of tuberculous pulmonary lesions not only for academic purposes, but also with a view to indications for surgery. This has led to divergent interpretations and inconsistent clinical conclusions. Contradictory explanations concerning epithelium, so frequently found in the lesions, have been the main cause of this divergence. Based upon the material available at Oteen we have attempted to analyze the evidence which has led to such difference in opinion, and have met with facts not previously reported which tend to clarify the picture. This paper deals mainly with the formation and healing of tuberculosis cavities. We are convinced that more consideration must be given to the bronchial tree than before. It appears that some still widely accepted views are no longer tenable. Pagel and Simmonds1 believe that in one mechanism of cavity healing ingrowth of epithelium occurs after the tuberculous process has been replaced by ordinary granulation tissue and fibrosis. Auerbach et al2’3’ 4 support this view, and express the opinion that this type of healing is rare except following streptomycin therapy where it is said to be nearly constant. According to them “re-epithelialization” of the “bronchocavitary junction” occurs regularly in the course of streptomycin therapy and “in some instances the epithelium extends far around the cavity wall,” preventing cavity closure. This is contrasted to non-streptomycin treated cases where they report that cavity closure follows bronchial occlusion, but Silverman et aP find that this very mechanism of closure follows streptomycin therapy, and do not mention epithelialization. Both Auerbach and Silverman agree that the cavity contents are potentially dangerous. However they disagree in the reasoning about the danger. Silverman, who claims that early cavity closure occurs with chemotherapy, is fearful about the subsequent retention of infectious material. Auerbach argues that the danger is brought about by non-closure of the cavity because of “re-epithelialization” induced by chemotherapy and is apprehensive about the infectious material because it can not be retained. Both conclusions cannot stand. Both authors have advised resection. In addition, Silverman, et al suggest the possibility that a cavity may start in a bronchus, but add that by the time the specimen is seen there is too much parenchymal involvement to permit clarification of this point. They also express the belief that tuberculous bronchitis occurs mainly following cavitation since none of their 22 cases had bronchitis