Abstract
Tridimensional photographic reconstruction of the lesions found in honeycomb lung in 10 different types of pulmonary disease was made. The pathological picture was characteristic and well defined by tridimensional microscopy and quite independent of the accompanying disease. The lesions responsible for its appearance involved the whole lobular bronchiolar system but were most marked in the terminal and respiratory bronchioli. The changes were fundamentally diffuse, saccular, and cystic bronchiolectasis. Other bronchiolar lesions were found such as changes in direction and mode of division, amputations, and anastomoses between bronchioles and cysts belonging to anatomically independent airways. There was some evidence that the bullous aspects of honeycomb lung were due to multiple valvular arrangements which let the air in but do not let it out. Honeycomb lung was, in the majority of cases, a complication of interstitial pulmonary fibrosis. Honeycombing was usually due to marked changes in the lobular bronchioles caused by the obliteration or rigidity of alveolar ducts and the corresponding alveoli and even by localization of the interstitial fibrosis in the bronchiolar wall.