Waldenström Macroglobulinemia-Induced Cardiac Amyloid Light Chain Amyloidosis.

Background: Waldenström macroglobulinemia is a rare cancer of plasma cells characterized by the excessive production of immunoglobulin M (IgM). IgM-associated systemic amyloid light chain (AL) amyloidosis is a rare complication of Waldenström macroglobulinemia, characterized by the misfolding of lambda light chains that deposit in various organs, including the heart. We describe a case of progressive nonischemic cardiomyopathy secondary to Waldenström macroglobulinemia and IgM-associated AL amyloidosis that was refractory to medical therapy and highlight the challenges in diagnosis and management. Case Report: A 64-year-old male with hypertension presented with symptoms of heart failure. Diagnostic workup revealed evidence of Waldenström macroglobulinemia and IgM-associated systemic AL amyloidosis affecting the heart. Further investigations confirmed the presence of Waldenström macroglobulinemia with lambda-restricted lymphoplasmacytic infiltrate in the bone marrow. Renal biopsy revealed amyloid nephropathy, and endomyocardial biopsy showed extensive deposits of fibrillary material consistent with cardiac amyloidosis. Because of the patient's advanced disease state and frailty, the decision was made to focus on comfort care with hospice. Conclusion: Waldenström macroglobulinemia-induced cardiac AL amyloidosis is a challenging clinical scenario characterized by the coexistence of 2 distinct hematologic disorders impacting cardiac function. Diagnosis requires a comprehensive evaluation, and management necessitates a multidisciplinary approach targeting both Waldenström macroglobulinemia and cardiac amyloidosis. Further research and collaboration are needed to improve diagnostic techniques, refine treatment approaches, and enhance patient outcomes for this rare and complex condition.