Bronchiolar pathology. I. Histopathology of small bronchi and bronchioli in some chronic lung diseases.

Different types of lesions in small bronchi and bronchioli in a hundred lungs or lobes resected for chronic lung diseases (suppurations, chronic pneumonitides, tumours) were evidenced and interpreted in the light of experimental results and in relation to the lung processes in their entirety. Inflammatory, exudative and proliferative lesions, primary and secondary changes, as well as evolutive modifications were discerned. Their structural analysis demonstrated the influence of persisting aerogenic agents of the infections, antigenic or common types, some correlations with the surrounding parenchyma primarily or secondarily involved, and possible mechanisms determining the lesions of small bronchi and bronchioli. Inflammatory changes of the lung tissue following those of bronchi are evident within chronic suppurations with or without bronchiolectasias, with a varied restructuration of the lung tissue. The role of the immunopathogenic component was emphasized not only in chronic pneumonitides, but also in other cases. Proliferative changes of respiratory bronchioli were only rarely found in distal zones of lungs resected for tumours. Relationships between bronchiolar lesions and parenchymatous changes of the centrolobular emphysema type were never evidenced in the analysed cases.