Multimodality Imaging in Monoclonal Gammopathy of Undetermined Significance and ATTR Wild-Type Cardiac Amyloidosis

Amyloidosis is characterized by the tissue deposition of insoluble fibrils derived from misfolded proteins. This case report describes a Hispanic man diagnosed with both monoclonal gammopathy of undetermined significance (MGUS) and wild-type transthyretin amyloidosis (ATTR) cardiac amyloidosis. The diagnosis was made using a combination of serological tests and multimodality cardiac imaging. The report highlights the importance of multimodality imaging in diagnosing cardiac amyloidosis, especially in cases where MGUS is also present. The patient presented with shortness of breath and was found to have cardiac abnormalities through electrocardiogram, echocardiogram, and cardiac magnetic resonance (CMR). A technetium-99m pyrophosphate (Tc-99m PYP) scan confirmed the presence of ATTR cardiac amyloidosis. Bone marrow biopsy confirmed MGUS. The patient was treated with diuretics and remained asymptomatic during follow-up. The report emphasizes the need for accurate diagnosis to differentiate between AL, ATTR, and MGUS due to their distinct clinical courses and treatments.