Bronchoalveolar lavage plasmacytosis in a patient with a plasma cell dyscrasia

A patient with serum monoclonal gammopathy, Bence-Jones proteinuria, and bone marrow plasmacytosis underwent fiberoptic bronchoscopic study for evaluation of interstitial lung disease. Bronchoalveolar lavage fluid contained 47 percent plasma cells, which were monoclonal by immunoperoxidase staining. This is the first time BAL plasmacytosis has been demonstrated in a patient with a plasma cell dyscrasia.