[Renal plasmacytoma].

Extramedullary plasmacytoma arising in the kidney is uncommon. So far only 11 cases have been reported. Recently, we noted the 12th case, the third case seen at the Kyoto University Hospital. The literature is reviewed. A 43-year-old man was hospitalized because of paraplegia due to spinal cord compression by the solitary plasmacytoma arising in the cervical spine, producing an IgG-lambda paraprotein. The tumor excision was followed by radiotherapy and standard chemotherapy. Two years later, new lesions on the thoracic spine, the left clavicle, and the occipital bone successively developed with Bence Jones proteinuria (lambda), but without IgG-lambda paraproteinemia. Ga-67 scanning was performed to detect extramedullary tumors. The marked accumulation of the radionuclide revealed intraabdominal tumors. A CT scan of the abdomen revealed a large soft-tissue mass (73 x 50 mm) emanating from the right kidney and several enlarged lymph nodes. Ultrasound of the right kidney revealed a solid mass with hydronephrotic change. RI-renogram showed delayed excretion from the right kidney. Clusters of myeloma cells were repeatedly observed in the urinary sediment. Thus, a diagnosis of plasmacytoma of the kidney was made. Treatment with radiotherapy alone was sufficient.