Transthoracic echocardiography (TTE) is a relatively precise method of evaluating intracardiac myxoma. However, if the cardiac myxoma is combined with other pathology, it could be missed by TTE. We report a case of a left atrial (LA) myxoma with mechanical mitral annular dilation and functional mitral stenosis (MS) combined with unrevealed atrial septal defects (ASD). A 52-year-old woman was admitted to the stroke unit with aphagia and right hemiplegia. Brain magnetic resonance imaging revealed an acute infarction in the left frontotemporal area. A TTE for a stroke cardiac work-up showed a giant LA mobile mass attached to the fossa ovalis, and surgery was scheduled for removal. Anesthesia was induced and maintained using targetcontrolled infusions (Orchestra Base Primea, Fresenius Vial, Brezins, France) of propofol (target concentration 1.2-1.3 mcg/ ml) and remifentanil (target concentration, 10-20 ng/ml). A preoperative TTE showed the disturbed left ventricle (LV) inflow myxoma during the diastole, with mild mitral regurgitation (MR). These findings suggested that the hemodynamic effect of the myxoma was severe MS, and we therefore carefully managed the ventricular preload and heart rate. Fluid was administered with monitoring of blood pressure, central venous pressure, pulmonary artery pressure and cardiac output, to maintain the preload, and phenylephrine was infused to prevent a decline in the systemic vascular resistance associated with remifentanil infusion. Dopamine was infused to preserve contractility. We used a transesophageal echocardiography (TEE) (X7-2t transducer and iE33; Phillips Healthcare, Andover, MA, USA) probe and evaluated the patient. An intraoperative TEE demonstrated that the mobile mass size was 54 × 29 mm in the LA, which was attached to the fossa ovalis (Fig. 1), and revealed a secondum type of ASD (Fig. 1) with a left to right shunt. The ASD was not identified on preoperative TTE. The LA mobile mass was prolapsed across the mitral valve into the LV during the diastolic phase, partially obstructed blood flow, and caused severe functional MS. MR was also found. However, the regurgitant flow was disturbed by the myxoma, and it was difficult to quantify with two-dimensional (2D) TEE. Real-time three-dimensional (3D) TEE using the en face surgical view from the LA demonstrated that the myxoma was located centrally over the mitral valve. In addition, 3D color doppler showed a central ellipsoidal MR almost reaching the LA superior wall. Three-dimensional imaging suggested more se vere regurgitation than appreciated by 2D imaging. An increased mitral valve annulus of 45 mm was observed. We noticed that the MR was significantly different from our preoperative expectations. The estimated pulmonary arterial systolic pressure was about 40 mmHg with plethora of the inferior vena cava. We reduced the phenylephrine infusion to lower the afterload so that the forward cardiac output was maximized. The LA mo bile mass was resected, including the atrial septum, resulting in enlargement of the ASD. The defect was repaired with a bovine pericardial patch. Mitral valve lifting annuloplasty via the appli cation of a flexible strip was also performed to reduce the dilated mitral valve annulus and correct the MR. After weaning from cardiopulmonary bypass, TEE confirmed complete resection of the LA mobile mass, closure of the ASD, and a well-functioning