In this article, we report an uncommon case of cardiac fibroelastoma originating from the left atrial septum. The mass moved from the mitral valve through the left ventricle in each atrial systole. However, the patient was free of any cardiac or cerebral symptom. Based on the echocardiographic findings, the mass was considered the left atrial myxoma and the patient was primarily scheduled for surgery. The mass which adhered to the left atrial septum was excised with the septum. Surgical septal defect was closed with an autologous pericardial patch. Intraoperative transesophageal echocardiography revealed no residual mass with a normal mitral valve function. The definitive diagnosis is made by histopathological examination. Papillary fibroelastomas originating from septum are extremely rare, but have high-risk for cerebrovascular embolism due to their location. Despite histopathologically benign nature, early diagnosis and treatment is of utmost importance due to fatal complication risks.

Keywords : Atrial septum; cardiac tumor; papillary fibroelastoma