Abstract
Multiple myeloma (MM) is typically characterized by the neoplastic proliferation of plasma cells producing a monoclonal immunoglobulin. Pleural effusion in MM is uncommon and usually caused by heart failure, pulmonary embolus, and nephrotic syndrome [<i>Arch Intern Med</i>. 1978;138(5):727–30; <i>Chest</i>. 1994;105(2):622–4]. Here, we report a case of myelomatous pleural effusion as part of the initial presentation of MM in a patient with the IgG-lambda subtype, which is extremely uncommon.