Cytologic and flowcytometric findings in a case of myelomatous pleural effusion: A rare and ominous presentation of multiple myeloma.

Plasma cell myeloma is a hematologic malignancy characterized by multifocal clonal proliferation of plasma cells usually associated with M protein secretion in serum and/or urine and evidence of organ damage. Generally, the presenting features are related to anemia, bone lesions, and renal failure. Pleural effusion is rare in multiple myeloma and when present is often due to nonmalignant causes. Myelomatous pleural effusion that is, effusions directly due to pleural infiltration by plasma cells is even rarer. We present a case of a patient presenting with dyspnea due to myelomatous pleural effusion. The fluid in such a case may be subjected to cytology examination, protein electrophoresis, flowcytometric analysis, and cytogenetics. The case highlights the utility of cytomorphology and flowcytometry in the diagnosis of myelomatous pleural effusion and also highlights that this type of presentation portends a poor prognosis to the patient.