We report the cases of six patients with pulmonary alveolar proteinosis (PAP). Four of the patients were adults, two males and two females (mean age 39 +/- 19 yrs). The other two patients were children, both females, one aged 6 years and one 3 days old. The diagnosis was made by thoracotomy-lung biopsy in two subjects, autopsy in two, transbronchoscopic biopsy in one and bronchoalveolar lavage (BAL) in one. Some of our cases presented unusual associations that have not been described previously in the medical literature: renal tubular acidosis, Fanconi's disease, glioblastoma multiforme and atrioventricular septal defect. In two patients, treatment with acetylcysteine and ambroxol was unsuccessful. Therapeutic BAL improved the clinical, analytical, functional and radiological aspects of two cases. In one subject, three months after the diagnosis of PAP, pulmonary tuberculosis appeared. Both diseases disappeared with antituberculous treatment.