The ascending aorta may be the site of origin of systemic embolization
in some cases that do not have an identifiable source. We report a ca
se in which a free-floating thrombus in the noncoronary sinus of Valsa
lva was detected by transesophageal echocardiography as a source of le
ft axillary artery embolism. After removal of this pedunculated thromb
us of unknown cause, which was attached on a macroscopically and histo
logically normal aortic wall, the patient made an uneventful recovery.