Abstract
As regards the pathogenesis of pulmonary aspergilloma, it has generally been approved that fungus grows as a saprophyte in preexisting cavity of tuberculous or bronchiectatic origin to form a intracavitary fungus ball, and no invasion of fungi occurs into the surrounding tissue. Detailed histological study of lung specimens resected from 13 patients with aspergilloma gave us, however, a result fairly different from this theory. Pericavitary or distant invasion of fungi was found in all cases, mostly in cavitary or bronchial wall and lymphoid follicle, rarely in lymphnode capsule or blood vessel wall. We found two types of tissue reaction: acute exudative or chronic productive, the latter being characterized by foreign body giant cell granuloma. Allergy and immunity might play a certain role in the progress of disease, as on one hand fungi were few and shrunken within the lesion, on the other remarkable was the tissue reaction such as proliferation of lymphoid follicle, together with positive serum precipitin test and increased immunoglobulin. Aforementioned histological study and analysis of special cases led us to the assumption that initial focus of fungal infection might be central part of bronchial tree, destructing lung tissue peripherally with cavity formation by antigen-antibody reaction and tumorous growth in situ acting as a check-valve. This hypothesis is based on the knowledge of the primary type of aspergilloma, but may be in part applicable to the secondary one.
