Pleural effusion as the first sign of multiple myeloma

Multiple myeloma (MM) is a rare disorder that affects all tissues, except reticuloendothelial tissues, and seldom causes a myelomatous pleural effusion. A 56-year-old male patient attended our clinic complaining of shortness of breath and fatigue for the past month. A posteroanterior chest radiograph revealed a left pleural effusion, which was subsequently assessed as being exudative in nature. Protein electrophoresis demonstrated hypergammaglobulinemia. Serum and pleural fluid immunofixation electrophoresis showed an increase in the IgG and kappa fractions. The Bence-Jones protein level in the 24-hours urine was high. Pleural biopsy showed plasmocyte infiltration. Bone marrow biopsy revealed atypical plasma cell infiltration, some with immature morphology, carrying IgG/Kappa clonality in a diffuse pattern. The patient was diagnosed with IgG/k type MM and underwent chemotherapy with vincristine, doxorubicin, and prednisolone. Complete regression of the pleural effusion was achieved after one round of chemotherapy, and the patient has been followed for 18 months.