From 1982-90, 3721 fiber bronchoscopies were performed for the diagnostics of diffused alveolar-septal pathologies; BAL was performed in 400 cases. Alveolar pulmonary microlithiasis was diagnosed in 6 patients, and two of them were related. The staging and the evolution of the pathology were evaluated as follows: chest x-ray in various projections, calcemia, lung function tests, fiber bronchoscopy with analysis of BAL and quantitative evaluation of macrophagic and lympho-monocytic elements and in percentage of calcosferitics. Four patients were treated with therapeutic BAL in the lungs with normal saline, and the cytological results and the percentage of calcosferitics were monitored for 24 months.