A 43-year-old woman without relevant medical history presented with acute middle cerebral artery (MCA) occlusion (figure 1A). Thrombophilia and vasculitis were ruled out and echocardiography was normal. Carotid web was considered because a shelf-like protrusion arising from the left carotid bulb (figure 1C) was found, which is suspected as the cause of embolization in MCA.1 Carotid endarterectomy was performed. The diaphragm-like structure demonstrated smooth muscle cell–rich intima, increased elastic tissue, and myxoid degeneration (figure 2, A and B). The superimposed thrombosis was identified in the web pocket (figure 2C). Postoperative CT angiography showed spontaneous recanalization of left MCA (figure 1B).