Successful treatment of recurrent cardiac sarcoidosis with the combination of corticosteroid and methotrexate monitored by (18)F-fluoro-2-deoxyglucose positron emission tomography: case series

BACKGROUND: The standard treatment for cardiac sarcoidosis (CS) is corticosteroids, including prednisolone (PSL). Previous studies have shown that the addition of methotrexate (MTX) to PSL is effective for steroid-refractory and recurrent cases. (18)F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) is an essential tool for the diagnosis of CS. However, it is unclear whether FDG-PET is useful for detecting recurrence of CS and monitoring the effectiveness of PSL and MTX combination therapy. CASE SUMMARY: We detected CS recurrence during PSL treatment using FDG-PET. Patient 1 was accompanied by increased FDG uptake in other organs, Patient 2 was complicated with a decrease in left ventricular ejection fraction, and Patient 3 showed enlargement of the late gadolinium enhancement area, which was compatible with the recurrence of CS. We successfully monitored the inflammation activity by FDG-PET and treated recurrent CS by increasing the PSL dose and adding MTX to suppress inflammation. DISCUSSION: FDG-PET is useful for detecting CS recurrence and monitoring the effectiveness of PSL and MTX combination therapy. Serial FDG-PET scans indicated that it might be more difficult to suppress inflammation in recurrent CS than in the initial treatment. The use of FDG-PET is necessary to monitor long-term disease activity.