Myxomas are by far the most common tumours of the heart. A 75-year-old man with no notable medical history presented with a 2-month progressive weight loss and dyspnoea on exertion. Physical examination revealed an opening snap and a diastolic decrescendo murmur at the apex. Transthoracic echocardiography showed a large, 85 × 30 mm, mobile, polypoid mass arising from the atrial fossa ovalis and protruding into the left ventricle during diastole. Irregular shape, multilobated surface and soft-tissue echogenicity were consistent with emboligenic myxoma. Surgical inspection confirmed a reddish gelatinous myxoma with villous, friable, thrombus-like surface prone to embolize. The mass was successfully removed and the histologic report confirmed the diagnosis.At 3-year follow-up, the patient is asymptomatic and no further mass has been detected. The case confirms that echocardiography remains a primary tool for the assessment of cardiac masses, providing morphological clues to define the potential risk of complications such as valve obstruction and systemic embolization.