A 62-year-old woman presented with a history of dyslipidemia, hypertension, and kidney transplantation 23 years prior due to chronic kidney insufficiency of unknown cause. She was treated with cyclosporine and mycophenolate mofetil. Due to complaints of tiredness and precordial oppression, transthoracic echocardiography was ordered by a nephrologist. The exam revealed a left atrial mass with irregular edges that very mobile and apparently adherent to the interatrial septum / posterior wall of the left atrium (Figure 1 and Movie 1). The left ventricle ejection fraction was normal and the remaining exam was unremarkable. The patient was hospitalized for close surveillance and study of the left atrial mass. She underwent transesophageal echocardiography that confirmed a large mass (2.5 cm in diameter), friable and very mobile, non-pediculated with a large, 1.4-cm base, apparently adherent to the transition between the left atrium posterior wall and interatrial septum, just above the mitral annulus (Figures 2 and 3). During atrial systole, this mass exhibited a slight protrusion into the mitral valve, not exceeding the valvular coaptation plan, causing no obstruction nor significant regurgitation (Movie 2). Cardiac magnetic resonance imaging (MRI) was also performed, showing a high-intensity signal on fluid-sensitive and fat-suppressed MRI, and heterogeneous mild late contrast enhancement (Figure 4, Movie 3). The mass did not appear to invade adjacent structures, which favored the diagnosis of a benign tumor. The patient underwent surgery to remove the mass. Pathologic analysis confirmed the diagnosis of a cardiac myxoma.