A case of juvenile cerebral infarction in which thrombus at carotid web was detected by carotid ultrasound

A 42-year-old man with aphasia and right hemiparesis thought to be caused by a middle cerebral artery branch occlusion and consistent with an embolic stroke was referred to our hospital for further evaluation and treatment. Imaging studies failed to identify the embolic source of the stroke, although a lesion protruding into the proximal portion of the left internal artery lumen was demonstrated on carotid ultrasonography. Specifically, the protruding lesion was a crescent-shaped membranous structure however, we did not initially regard the protruding lesion as the embolic source. Therefore, he was treated with warfarin and followed in the outpatient clinic. Serial carotid ultrasonographic examinations performed at each outpatient clinic visit revealed no structural changes in the crescent-shaped membranous structure, but a thrombus distal to the membranous structure was detected 6 months after the stroke onset in spite of warfarin therapy. At that time, we determined that the protruding lesion was a carotid web and the embolic source of the stroke. He underwent a carotid endarterectomy, the warfarin was discontinued, and he has had no recurrent strokes. A carotid web is an important embolic source of an ischemic stroke, but has not been widely reported. It is essential to recognize a carotid web as a potential embolic source to prevent stroke recurrence.