The structure of bronchial plugs in mucoid impaction, bronchocentric granulomatosis and asthma.
The structure of bronchial plugs was examined in 12 lobectomy specimens from patients with bronchocentric granulomatosis and mucoid impaction, two bronchial biopsies from patients with mucoid impaction, sections from one post-mortem showing evidence of mucoid impaction and bronchocentric granulomatosis as well as aspergilloma with tissue invasion and from post-mortems on eight patients who had died during a persisting exacerbation of their asthma. In both mucoid impaction and asthma eosinophils were arranged in layers within the mucus, but the pattern of lamination was different in the two groups. In asthma the layers of eosinophils appeared as whorls and eddies. In mucoid impaction the lamination was parallel to the circumference of the plug and the eosinophils were tightly compacted and appeared degenerate; fungal elements were found in all cases and were more readily seen among the eosinophils than in the mucus. The histological appearance of even small fragments of such plugs is diagnostic of allergic bronchopulmonary fungal disease with mucoid impaction. In all our cases bronchocentric granulomatosis appears to have been a complication of allergic bronchopulmonary aspergillosis with mucoid impaction. The clusters of inspissated eosinophils so typical of the peripheral lesion of bronchocentric granulomatosis appear to be fragments of the mucus plugs formed in the larger bronchi.