Abstract
BACKGROUND: Amyloidosis is a disorder characterized by misfolded protein deposits in organs, often manifesting as cardiac disease. CASE SUMMARY: A 60-year-old male with a history of isolated proteinuria and recent fat biopsy-proven transthyretin (TTR) amyloidosis was referred to us for evaluation of cardiac involvement with amyloidosis. He underwent a technetium pyrophosphate scan which showed Perugini grade 3 uptake concerning for cardiac involvement. His persistent proteinuria and serum IgG kappa monoclonal protein raised suspicion for light-chain (AL) amyloidosis. Endomyocardial biopsy confirmed TTR cardiac amyloidosis, while a subsequent kidney biopsy and bone marrow evaluation revealed renal-limited AL kappa amyloidosis. DISCUSSION: This rare presentation highlights the challenge of distinguishing between TTR and AL amyloidosis, especially with atypical features. It underscores the necessity for tissue diagnosis and mass spectrometry in complex cases, even with seemingly concordant noninvasive findings.