Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 4 2 2009 04 16 121 124 Sima Rafeiyian Shaheed Modarres Hospital, Shaheed Beheshti University of Medical Sciences (SUMS), Tehran, Iran. Manouchehr Hekmat Shaheed Modarres Hospital, Shaheed Beheshti University of Medical Sciences (SUMS), Tehran, Iran. Ali Kouhi Amir Alam Hospital, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 03 Hydatid disease, caused by echinococcus granulosus, is a common infectious disease in endemic areas such as Southern Europe and the Middle East. The incidence of this disease, however, is on the increase in Northern Europe due to the migration of labor and also tourism. We report a case of the hydatid cyst of the mediastinum, the diagnosis of which was established by the hemagglutinin test and echocardiography and confirmed by histological examinations. The cyst was totally removed during surgery on beating heart. The patient presented herein demonstrates that the mediastinal and cardiac involvement in hydatid disease could manifest in children with fast growth and rupture. https://rhythm.tums.ac.ir/index.php/jthc/article/view/131 https://rhythm.tums.ac.ir/index.php/jthc/article/download/131/129