[Interatrial defect functionally cancelled by a left atrial myxoma within the framework of embolizing mitral stenosis and insufficiency].

The case is presented by a 54 year-old woman, studied because of a clinical diagnosis of mitral valve disease, in which echocardiographic and angiocardiographic examination afforded the diagnosis of left atrial tumor. The surgical finding was of a large myxoma implanted on the atrial septum and prolapsing into the mitral opening and engaging with a branch into an atrial septal defect of the cavalis superior type. Some considerations are made on the times of possible origin and growth of the tumor; the complete absence of the increased pulmonary flow in the presence of a large interatrial communication suggested an early beginning of the tumor that, obstructing the defect, might have hindered the hemodynamic derangement.