Isolated primary cardiac sarcoidosis presenting as acute heart failure.

A 65-year-old man was referred to our hospital due to an acute onset of dyspnea and persistent fever. Echocardiography revealed an ejection fraction (EF) of 25% with diffuse severe left ventricular (LV) dysfunction. 18F-fluorodeoxy glucose-positron emission tomography imaging showed significantly increased uptake by the LV and right ventricular walls, indicating active inflammation. The histologic findings of the endomyocardial biopsy specimens indicated the presence of epithelioid cell granuloma. The final diagnosis was thus cardiac sarcoidosis with acute inflammation. Five-months after the initiation of steroid therapy, echocardiography showed an EF of 50%. This is a rare case in which acute inflammation led to acute heart failure mimicking acute myocarditis.