Diffuse Cystic Lungs of Granulomatous Origin: A Histological Study of Six Cases

Abstract

Detailed histological studies on 6 cases of honeycomb lungs are reported with brief clinical histories. All cases showed a granulomatous process in the walls of the cysts and in the inter-cystic spaces. In the acute phase this process was characterized by a highly cellular histiocytic response, and in the chronic phase by wide-spread fibrosis. In the intermediate stages, foamy macrophages were present in large numbers, sometimes being the predominant cell. It is suggested that the cystic spaces are produced by weakening of the walls of the smaller bronchioles as a result of granulomatous infiltration. Distinction between cysts of bronchiolar and alveolar origin is impossible. 3 of the 6 cases showed evidence of extrapulmonary disease, 2 having a similar granuloma of the liver, and 1 had transient diabetes insipidus, suggesting pituitary involvement. There is a close similarity between these 6 cases and what has been termed eosinophilic xanthomatous granuloma. The authors state that it is likely that such a granuloma is a nonspecific pathological response to a number of etiological agents,and that grouping them together on histological grounds may be unjustifiable.