Floating thrombus originating from an almost normal thoracic aorta.

We present a case of floating thrombus originating from an almost normal thoracic aorta in a 54-year-old man who presented with acute arterial occlusion of his left leg. Transesophageal echocardiography (TEE), computed tomography, and magnetic resonance imaging showed two masses in an almost normal aorta after embolectomy for the acute arterial occlusion. Although the embolus was thrombus histologically, malignant tumors could not be ruled out. The masses did not decrease in size after 7 days of anticoagulant therapy, so they were extirpated under cardiopulmonary bypass (CPB) and TEE guidance. Frozen section examination during CPB indicated that there was no evidence of malignancy in the removed mass. TEE played an important role in the diagnosis and surgery of this condition, and it was useful when deciding on a surgical strategy. Because the treatment strategy for this disease remains controversial, further studies are needed.