IgM-monoclonal gammopathy associated with malignant lymphoma with recurrent pleural effusion

A case of malignant lymphoma (plasmacytoid lymphocytic type) with IgM-monoclonal gammopathy is presented. The main site of lesion was in the lung. The sole clinical manifestation was pleuropulmonary involvement with massive pleural effusion. A clue to the diagnosis was given by cytological and immunocytological examination of pleural aspirates. Subsequent immunological survey of serum protein and a bronchial biopsy confirmed the diagnosis.