Abstract
BACKGROUND: Large intracardiac bronchogenic cysts are rare mediastinal masses. However, they must always be considered in the differential diagnosis of heart failure with abnormal chest X-ray. CASE PRESENTATION: We present a 60-year-old female patient with de novo atrial fibrillation, heart failure and a very large intrapericardial mass. The patient underwent successful surgical resection, with pathological findings confirming a bronchogenic cyst. CONCLUSIONS: Large bronchogenic cysts located intrapericardially are very rare. However, they should be included in the differential diagnosis of patients presenting with atrial fibrillation and heart failure with abnormal radiologic studies.