Can Systemic Sarcoidosis and Genetic Cardiomyopathy Coexist?

Genetic cardiomyopathies and cardiac sarcoidosis share overlapping features, complicating diagnosis when both conditions coexist. We describe 3 patients with filamin C-associated, plakophilin-2-associated, and MYBPC3-associated cardiomyopathies who were later diagnosed with extracardiac sarcoidosis. Despite imaging findings concerning cardiac sarcoidosis, only 1 patient demonstrated active myocardial inflammation warranting immunosuppression; the others were managed as primary genetic cardiomyopathy. These cases illustrate the limited specificity of cardiac imaging in patients with known genetic cardiomyopathy and highlight the need for careful, individualized assessment to determine whether sarcoid inflammation contributes to arrhythmias or ventricular dysfunction.