A Case of Internal Carotid Artery Occlusion Caused by En Bloc Distal Embolization of Carotid Free-Floating Thrombus Treated by Mechanical Thrombectomy

OBJECTIVE: We report a case of internal carotid artery (ICA) occlusion caused by en bloc distal embolization of carotid free-floating thrombus (FFT) treated by mechanical thrombectomy. CASE PRESENTATION: A 57-year-old woman was brought to our hospital with dysarthria, right hemiparesis, and motor aphasia. MRI and MRA revealed acute infarction due to middle cerebral artery occlusion. Carotid ultrasonography demonstrated a pedunculated mobile plaque in the left ICA. We diagnosed embolic infarction due to the carotid FFT and started medical treatment. However, on the second hospital day, the carotid FFT detached from the arterial wall en bloc, resulting in left ICA occlusion. The occluded ICA was successfully recanalized by mechanical thrombectomy. CONCLUSION: FFT is associated with a high risk of embolic ischemic stroke and the primary treatment strategy must be carefully considered.