Two Discrete κ Light Chain Peaks Discovered During Follow-up of a Patient With Multiple Myeloma

Monocloncal protein (M-protein) is a cloncal immnoglobulin produced by malignant plasma cells. It is not uncommon to detect more than 1 M-protein in multiple myeloma (MM) and this can stem from 2 kinds of M-proteins produced by a single B cell clone or from 2 separate clones. Herein, we report our detection, via urine immunoelectrophoresis, of 2 κ light chain peaks in a 77-year-old female patient with MM. The patient without significant adverse events in her medical history presented with clavicular fracture and was admitted to the Department of Orthopedics. There was no remarkable laboratory findings except a significant elevation of κ free light chain (FLC) and FLC ratio. After 10 months, bone marrow showed increased plasma cells in touch imprints and urine capillary electrophoresis revealed 2 separate peaks in the gamma region, which were found to be κ light chain (LC) via immunotyping. We found 2 separate FLCs in our patient that were not detected initially by immunoelectrophoresis, but were found during follow-up with BM examination; elevated LCs had previously been detected via FLC analysis.