Rare Complication of a Rare Malignancy: Case Report of Cardiac Amyloidosis Secondary to Waldenstrom Macroglobulinemia.

Cardiac amyloidosis is a rare disorder caused by the myocardial deposition of abnormal fibrils. A 52-year-old man was referred to our center with clinical features of heart failure, after cardiac magnetic resonance imaging showed restrictive cardiomyopathy. Abdominal fat pad biopsy showed features of amyloidosis, and after hematological workup, he was diagnosed with Waldenstrom macroglobulinemia (WM). He was initiated on a rituximab-based chemotherapy regimen, and his cardiac function was assessed serially. Because of non-response, he was switched to a bortezomib-based regimen. Unfortunately, three days into this regimen, the patient died. WM is a rare plasma cell dyscrasia with a nonspecific presentation. It uncommonly presents with sequelae of amyloidosis-the IgM subtype of amyloid-light chain (AL) amyloidosis. Diagnostic delays are common, contributing to an already poor prognosis. Amyloidosis in WM requires urgent treatment - clonal chemotherapy, and supportive cardiac care in heart involvement. Bortezomib-based regimens are commonly recommended, with diuretics as the mainstay for cardiac treatment. However, in most advanced cases, the prognosis is poor; thus, a high degree of suspicion is necessary for early diagnosis. This case illustrates the possible presentation of cardiac amyloidosis as a rare malignancy.