A 7-y-old girl presented with prolonged fever, arrhythmia and cardiomegaly during the treatment course of group A β-haemolytic streptococcal pharyngitis. The isolated rheumatogenic strain M1 suggested the diagnosis of rheumatic fever. However, serous pericardial effusion contained high levels of Epstein-Barr virus (EBV) DNA. Clonally proliferating EBV+ T cells were determined in the circulation. The atypical carditis without valvitis was then complicated by coronary artery dilatations. Four months after the start of prednisolone plus antiviral/bacterial therapy, EBV+ T-cell lymphoma developed in the thigh.Conclusion:
Atypical carditis may be a notable and life-threatening presentation of chronic active EBV infection to be differentiated from rheumatic fever.