Light Chain (AL) Cardiac Amyloidosis: A Diagnostic Dilemma

Amyloidosis is a clinical condition characterized by amyloid fibril deposition into different organ systems. The most common types are light chain (AL) amyloidosis and transthyretin amyloidosis (ATTR) amyloidosis. Amyloidosis involves the heart with an incidence of 1.38 to 3.69 per 100,000 person-years and a prevalence of 14.85 per 100,000 person-years between 2004 and 2018. Diagnosis of cardiac amyloidosis can be made through cardiac imaging, including cardiac magnetic resonance imaging (CMR) and 99mTc-labeled pyrophosphate (PYP) cardiac scan. However, a tissue biopsy is frequently needed to confirm the diagnosis. Herein, we report such a case of cardiac amyloidosis. The patient presented with pericardial effusion and acute kidney injury as the initial presentation. The presumptive diagnosis was ATTR amyloidosis, but the endomyocardial biopsy confirmed the diagnosis of AL amyloidosis. The patient was started on bortezomib, cyclophosphamide, and dexamethasone therapy. We aimed to highlight the different diagnostic modalities of cardiac amyloidosis and the importance of obtaining tissue biopsy to confirm the amyloidosis type before starting the treatment.