Abstract
A 47-year-old male with macroglossia presented with dyspnea on effort and chest pain at rest. Cardiac MRI revealed diffuse global subendocardial late gadolinium enhancement below the left ventricular endocardium and a dark blood pool of intracardiac contrast medium. Tongue biopsy revealed amyloid deposition, which was limited in the myocardium. He was diagnosed with primary light chain amyloidosis. His condition was stage I according to the Mayo Clinic staging system. He underwent autologous peripheral blood stem cell transplantation. On Day 10, he developed chest pain and died suddenly on Day 11. Postmortem examination revealed amyloid deposition throughout the heart.