A 47-year-old man presented to the emergency department for 2 episodes of twitching in the left arm that occurred in the last 24 hours. The neurological evaluation, electroencephalographic monitoring, computed tomographic (CT) scan, carotid arteries ultrasound, and electrocardiogram were unremarkable. To exclude cardiogenic causes of embolism, transthoracic and transesophageal echocardiography were performed. A giant floppy and friable mass (28 × 38 mm) implanted on the left side of the interatrial septum with a diastolic prolapse into mitral valve orifice was discovered.

During the transesophageal examination, an embolization of a mass fragment (18 × 13 mm) in the aorta occurred (A, Online Video 1). A second, urgent neurological evaluation and a CT scan were performed, but both resulted negative. The left side interatrial septum localization and consistency were highly suggestive of an atrial myxoma. The patient underwent surgical mass excision the following day, and the diagnosis was confirmed by histopathology.