Successful treatment of recurrent cardiac sarcoidosis with the combination of corticosteroid and methotrexate monitored by 18F-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. 18F-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.