[Pathology of bronchopulmonary aspergillosis]

This paper concerns the morphology of 3 types of bronchopulmonary aspergillosis: saprophytic aspergillosis (SPA), invasive aspergillosis (IVA) and allergic bronchopulmonary aspergillosis (ABPA)/allergic bronchopulmonary mycosis (ABPM). To know whether Aspergillus (ASP) in SPA only colonizes in preexisting cavities or presents significant pathogenecity, we examined 38 surgical specimens of SPA and 10 post-tuberculous open cavities (PT-OC). Macroscopically, SPA cavities had macroscopic ulcers (81.6%) and bronchi originating from the cavities (68.4%), in contrary to PT-OC that had neither of them. Microscopically, SPA cavities showed shallow ulcers (100%), coagulation necrosis (42.1%) and granulomatous reaction (52.6%), although ASP invasion to the viable lung tissue couldn't be discovered. The lung tissue around the SPA cavities showed various inflammation caused by transbronchial ASP dissemination from the cavities. We concluded that (1) SPA should be considered chronic destructive infection by ASP, but not colonization, (2) SPA couldn't be differentiated in quality from semi-invasive/chronic necrotizing pulmonary aspergillosis, and both should be categorized into secondary bronchopulmonary aspergillosis. Respecting IVA, we investigated 10 autopsy cases. In those cases, the disease was brought about in the lungs having no preexisting lesions. Three forms were distinguished; (1) 5 cases in that coagulation necrosis was a main feature (CN-IVA). (2) 2 cases having lung balls in cavitary lesions (LB-IVA), and (3) 3 cases showing suppurative lesions (SP-IVA). In CN-IVA and LB-IVA cases, ASP invaded to the viable lung tissue. But in 2 cases of SP-IVA, fungal hyphae were identified only in necrotic lesions but not in the viable tissue. Because the "invasive" was vague in definition, we should categorized these cases into primary bronchopulmonary aspergillosis. To determine the primary lesion of ABPA/ABPM, 5 lobectomy specimen were examined. All cases had hard or firm mucous plugs in the proximal bronchi, peripheral to which we found inflammation with tissue eosinophilia (bronchocentric granulomatosis with tissue eosinophilia : 5 cases, xanthogranuloma-like lesions : 2 cases, eosinophilic pneumonia : 2 cases and organizing pneumonia : 4 cases). Conglomerates of degenerated eosinophils, sometimes showing fir-structure, and fungal hyphae were recognized in both of mucous plugs and the peripheral lesions. We concluded that the mucous plug was the primary lesion of ABPA/ABPM.