A 69-year-old patient with dilated cardiomyopathy and atrial fibrillation experienced a transient ischemic attack. A septal pouch was diagnosed by transesophageal echocardiography and a mass into the pouch was detected, which was initially defined as thrombotic material. Since the mass did not disappear after a period of effective anticoagulation, a different etiology was suspected and cardiac magnetic resonance showed a lipomatous nature. As far as we know this is the first case of septal pouch lipoma.