Diagnosing Smoldering Multiple Myeloma and Light Chain Amyloidosis in the Setting of Severe Transthyretin Amyloid Cardiomyopathy and Extracardiac Sarcoidosis

Abstract

Light chain (AL) amyloidosis involves deposition of monoclonal immunoglobulin light chain-derived amyloid fibrils, whereas ATTR amyloidosis involves deposition of insoluble antiparallel beta-pleated protein within tissues, leading to organ-specific damage. Regardless of ATTR amyloid status, serum protein electrophoresis with immunofixation is appropriate in cases of cardiac amyloidosis, as treatment of an underlying plasma cell dyscrasia drastically differs. This case illustrates the importance of universal screening for AL amyloidosis in the context of clinical findings for cardiac amyloidosis.