Extrapulmonary sarcoidosis involving only the heart and guts: a case report.

Background: The respiratory tract is the most commonly affected organ system in sarcoidosis. Purely extrapulmonary sarcoidosis is rare. There have been no reports of extrapulmonary sarcoidosis with lesions only in the heart and guts. Case summary: A 19-year-old male was admitted for chest symptoms accompanied by remarkably elevated troponin T and creatinine kinase levels. Electrocardiogram (ECG) showed sinus rhythm with a right bundle branch block, broad ST segment elevation, and abnormal Q waves. Endoscopic biopsy revealed granuloma formation in the transverse colon. Based on multimodal imaging, we made a clinical diagnosis of extrapulmonary sarcoidosis involving only the heart and guts. One year of immunosuppressive therapy with prednisolone resolved the inflammation in the guts but not in the heart. He experienced runs of sustained ventricular tachycardia with loss of consciousness and was admitted to our hospital again. The addition of methotrexate markedly reduced cardiac accumulation of fluorodeoxyglucose. No life-threatening ventricular arrhythmias have been recorded afterwards. Discussion: This unusual case of cardiac sarcoidosis not only involved rare lesions only in the heart and guts but also presented with ST elevation on ECG. This case suggests that the gastrointestinal tract is a site of effective antigen capture outside of the respiratory tract that can affect the heart.