Pulmonary alveolar proteinosis: the diagnosis by segmental lavage.

Histologic findings from segmental lavage material via the fiberoptic bronchoscope were evaluated as a means of diagnosing pulmonary alveolar proteinosis. Active cases of alveolar proteinosis yielded grossly opaque and/or milky effluents. The unique histologic findings in alveolar proteinosis included: (1) very few alveolar macrophages (2) large acellular eosinophilic bodies in a diffuse background of eosinophilic granules, and (3) periodic acid-Schiff staining of the proteinaceous material with a lack of significant alcian blue staining. Thus, the diagnosis of pulmonary alveolar proteinosis can be made by evaluation of the clinical setting and histologic findings of the effluent material from a segmental lavage.