Giant interatrial septal aneurysm mimicking a right atrial tumor.

We report the case of a patient with a giant interatrial septum aneurysm who was admitted to our hospital for analysis of palpitations. Transthoracic echocardiography was not contributive and cardiac magnetic resonance imaging demonstrated a small interatrial septal aneurysm. In our study, only transesophageal echocardiography provided the correct diagnosis, showing a giant interatrial septal aneurysm protruding far away into the right atrium and mimicking a right atrial cystic tumor.