The role of bronchial biopsy and washing in the diagnosis of allergic bronchopulmonary aspergillosis

The diagnosis of allergic bronchopulmonary aspergillosis (ABPA) is usually established on the basis of clinical, serologic, and radiologic criteria, of which eight are commonly cited. Although histologic abnormalities are not usually considered, a study of lobectomy/lung biopsy specimens provided evidence that the combination of mucoid impaction of bronchi with 'allergic' mucin and fungal hyphae is diagnostic of ABPA. We attempted to explore the use of surgical specimens in the diagnosis of ABPA by examining endobronchial biopsy specimens and washings. Bronchial biopsy specimens obtained from 1990 to 1995 that contained fungal hyphae were reviewed and assessed for the presence of 'allergic' mucin and bronchial wall abnormalities. We also reviewed cytologic specimens and clinical, serologic, and radiologic findings of the corresponding patients. Five biopsy specimens had fungal hyphae and associated 'allergic' mucin. In some patients, the mucin was small in amount and contained degenerated eosinophils that resembled macrophages. None of the patients was thought to have ABPA clinically. All of the five had bronchial mucoid impaction at bronchoscopy. After additional investigation, only one patient fulfilled all of the eight traditional criteria for ABPA; one other patient fulfilled six criteria. Although some tests were not completed in the remaining three patients, follow-up and/or response to steroids was consistent with ABPA in all of the three. Four patients had bronchial washing performed at the time of biopsy. Cytologic examination showed one to be normal except for inflammatory cells that did not include eosinophils; three others showed mucus containing eosinophils intermixed with Charcot-Leyden crystals and scattered hyphae. We conclude that patients with ABPA might have atypical manifestations of disease and not meet standard diagnostic criteria. Bronchoscopy with bronchial biopsy and washing plays a role in detecting these patients. The presence of 'allergic' mucin might be overlooked in the small biopsy fragments obtained by bronchoscopy.