Multiple myeloma-associated light chain amyloidosis involving heart, kidneys, and peripheral nerves

Abstract

Abstract Introduction: Multiple myeloma (MM) is a hematologic malignancy characterized by the clonal proliferation of monoclonal protein-producing plasma cells and can cause immunoglobulin light chain (AL) amyloidosis. Although MM-associated AL amyloidosis is rare, it can significantly increase patient mortality, as its various non-specific symptoms can delay diagnosis and treatment. Patient concerns: A 77-year-old female patient visited a renal clinic with complaints of generalized edema and dyspnea (New York Heart Association class III) persisting for three weeks. The patient had hypoalbuminemia, mild anemia, and nephrotic-range proteinuria. Echocardiography revealed concentric hypertrophy of the left ventricle and sparkling textures in the myocardium. Serum protein immunofixation revealed monoclonal gammopathy of immunoglobulin G/lambda light chain. A bone marrow biopsy showed 30% plasmacytosis scattered with cluster of differentiation 138-positive plasma cells. A kidney biopsy demonstrated a mesangial matrix positive for Congo red staining and deposition of amyloid fibrils on electron microscopy. Sensorimotor polyneuropathy was noted on the nerve conduction studies of both lower extremities. Diagnosis: The patient was diagnosed with heart failure, nephrotic syndrome, and peripheral neuropathy caused by MM-associated AL amyloidosis. Interventions: She was given supportive treatment upon admission, including administration of diuretics, albumin, and vasopressors, followed by combination chemotherapy (melphalan and dexamethasone). Outcomes: The patient's condition deteriorated due to heart failure and azotemia. She died from multiple organ failure on the 28th day of hospitalization. Conclusion: MM-associated AL amyloidosis can rapidly progress to fatal multiple organ failure. Therefore, if AL amyloidosis is suspected in patients with MM, prompt assessment of organ dysfunction and early initiation of intensive care including proper chemotherapy are required.