A 73-year-old woman came to our observation to perform a routine echocardiographic examination. The patient had arterial hypertension, dyslipidemia, hypothyroidism, and paroxysmal atrial fibrillation. She underwent a bilateral mastectomy for breast cancer about 5 years ago, and she was undergoing chemotherapy and radiation therapy for a stage IV lung adenocarcinoma. The clinical evaluation was normal, as was the electrocardiogram. The transthoracic echocardiographic evaluation showed the presence of a rounded formation with variable echogenicity, with an irregular surface (4 x 3 cm), adherent to the interatrial septum at the level of the fossa ovalis, which did not hinder the excursion of the mitral valve. No other significant cardiac abnormalities were detected.Transesophageal echocardiography confirmed the presence of atrial mass adhered to the oval fossa (panels A, B). of coarsely rounded shape, and variable echogenicity, in the absence of interference with the movement of the valve leaflets and of anomalies of the interatrial septum (panel C). Coronary angiography showed right-dominant coronary circulation (panel D) and mild stenosis of the mid-left anterior descending artery. Abundant arterial perfusion of the atrial mass, with several vessels originating from the circumflex artery, was also evident at the coronary angiography (panels E, F). The patient underwent cardiac surgery; the surgical exeresis of the left atrial mass was performed through right mini-thoracotomy (panels I and L). Because the neo-formation was adherent not only to the atrial septum but also to the left atrial roof, to obtain a radical excision, a large portion of the atrial wall and the septum were removed and totally reconstructed with the pericardium. The main artery supplied the mass-related vascular network was ligated. The postoperative course was uneventful, and the patient was discharged at home on day six. The pre-discharge echocardiography and the cardiac magnetic resonance ( panels G, H) showed the absence of any residual mass in the left atrium that appears anatomically reshaped, no shunt at the level of the interatrial septum, and preserved ventricular function of both ventricles. Histological analysis confirmed the diagnosis of atrial myxoma. At the six-month follow-up the patient was asymptomatic and the echocardiography was superimposable to discharge.