Abstract
Accurate amyloid typing in cardiac amyloidosis is clinically important for determining treatment strategies. A 73-year-old man underwent a renal biopsy due to renal dysfunction and was diagnosed with systemic λ-type light chain (AL) amyloidosis. Echocardiography and cardiac magnetic resonance revealed cardiac involvement, leading to a clinical diagnosis of λ-type AL-cardiomyopathy (CM). However, the clinical course and findings were inconsistent with AL-CM. Technetium-99m-pyrophosphate scintigraphy showed intense myocardial uptake corresponding to Grade 3 on visual assessment. Further examination through an endomyocardial biopsy and protein mass spectrometry revealed the patient had both AL-CM and transthyretin amyloid (ATTR)-CM. In addition to chemotherapy for systemic AL amyloidosis, transthyretin stabilizing therapy was initiated for wild-type ATTR-CM. Initially, this patient was diagnosed with AL-CM complicated by systemic AL amyloidosis; however, it was subsequently determined that the cardiac involvement was a coexistence of both AL-CM and ATTR-CM.