Reappearance of Free-floating Carotid Thrombus after Discontinuation of Anticoagulant Therapy

A 73-year-old woman who suddenly developed left hemiparesis was admitted to our hospital. Ultrasonography on admission showed a free-floating thrombus (FFT) attached to an ulcerative plaque in the right common carotid artery. The FFT almost disappeared during treatment with intravenous anticoagulation therapy for acute stroke, but it reappeared when the therapy was discontinued. She underwent endarterectomy on day 13, after which she was free from stroke recurrence.