A Case of Floating Aortic Arch Thrombosis in a Patient without Thrombophilia

Floating aortic arch thrombi—blood clots forming in an aorta without aneurysms or atherosclerosis—in a normal aorta are exceedingly rare. The etiology is unknown, and there are no guidelines for appropriate treatment strategies. We report a case of floating aortic arch thrombosis in a patient without coagulopathy that was treated surgically. As the mass could not be identified preoperatively as a tumor or thrombus, synthetic graft replacement was performed, allowing resection of the lesion site. Histopathological examination revealed erosion and fissures in the tunica intima of the aorta, which suggested vessel damage to the tunica intima as the cause.