[Pleural manifestations of secondary monoclonal dysproteinemia (apropos of 4 cases)].

A pleural effusion with monoclonal macroglobulinemia is not unusual outside Kahler and Waldenström diseases which are the two commonest. It can occur in lymphoid leucosis with plasma concentration peaks, where surface immunoglobulins play an important part, and in some epithelial cancers. As in primitive macroglobulinemia the plasma concentration peak corresponds to pleural globulin modifications. But it seems that, whatever the variations of pathological immunoglobulins, the pleural lymphocytes, predominant in the effusion, play an active part due to various etiological stimulations.