Cardiac mass as the primary diagnostic clue of Edheim-Chester disease.

Key Clinical Message: We introduced one of the rare causes of intra-cardiac mass, that is, ECD and a new gene mutation (SLC29A3) that is probably related to this disease, and we noted the importance of using several diagnostic methods to rule out other intra-cardiac causes. Abstract: Edheim-Chester disease is a rare histiocytosis affecting multiple organs. The infiltration of lipid-laden histiocytes characterizes the disease. Most patients experience bone involvement; over 50% of cases involve the cardiovascular system and other extra-osseous organs. In this case report, we present the case of a 42-year-old man who complained of shortness of breath and bone pain. During echocardiography, a large, homogenous, and fixed mass was found in the right atrium free wall. Computed tomography and cardiac magnetic resonance imaging revealed an infiltrative mass in the RA with atrioventricular groove involvement but coronary sinus encasement, right coronary artery, and superior vena cava encasement. Abdominal CT scans also reported aortic wall involvement and bilateral renal cortical and perirenal involvement. A kidney biopsy confirmed the infiltration of histiocytes and the diagnosis of ECD. The treatment was initiated for him, and his symptoms improved. In this case report, we express the importance of considering the rare causes of cardiac tumors.