Light Chain Escape Multiple Myeloma Complicated with Catastrophic Extramedullary Plasmacytoma Following Novel Agent Treatment

The treatment of multiple myeloma (MM) has made greatly advances over the last decade, nearly doubling the overall survival time after the use of novel agents such as thalidomide, lenalidomide and bortezomib. However, the improvement of overall survival has occasionally led to clinical scenarios that were rarely recognized before, for example, light chain escape and extramedullary plasmacytoma (EMP). Here we report an MM patient who relapsed and manifested simultaneously with both a light chain escape and a disseminated pattern of EMP after several different modes of treatment, including conventional chemotherapy, autologous peripheral blood stem cell (PBSC) transplantation, and novel agents. The result was disappointing in this case, which taught us several important things: First, intact immunoglobulin may not be a reliable marker in the surveillance of pretreated multiple myeloma. Various tests for renal function, skeletal condition, and serum free light chain should also be carried out for a comprehensive evaluation. Second, EMP remains a tremendous challenge to the clinician, especially when refractory to current novel agents. Further researches are required to clarify the optimal treatment of such a condition in order to help more patients.