IgD-kappa myeloma: an unusual case.

A rare case of biclonal IgD-kappa and IgG-kappa myeloma is described. The patient initially presented with anemia, renal insufficiency, and proteinuria. The IgD-kappa, initially, was overlooked as a light chain; however, it decreased in serum concentration after treatment by approximately 90%, in contrast to the IgG-kappa that decreased in serum by approximately 40 % over a 9-yr period. Clinically, the patient responded well to treatment and improved greatly during this period. Practical recommendations are suggested in order to detect such cases.