Cardiac Amyloid, The Great Imitator

Although endomyocardial biopsy (EMB) is the criterion standard for diagnosis of infiltrative cardiac disease, cardiac sarcoidosis (CS) or cardiac amyloid can be diagnosed noninvasively through both clinical suspicion and advanced imaging techniques of cardiac magnetic resonance imaging (CMR) or cardiac positron emission tomography (PET).

A 79-year-old man with mediastinal sarcoidosis presented with new chest pain and a right bundle branch block, raising concern for CS. CMR and cardiac PET also supported the diagnosis of CS, but EMB ultimately revealed transthyretin amyloid cardiomyopathy. The patient was started on tafamidis and showed improvement at 1-year follow-up.

This case shows that cardiac amyloidosis can masquerade as CS when following conventional diagnostic pathways. Without EMB, this patient would have been treated with steroids for CS, which is not a risk-free therapy.

It is possible to misdiagnose CS in the setting of amyloidosis when using advanced noninvasive imaging techniques such as CMR and cardiac PET.