A 61-year-old Han man presented to our hospital with intermittent dizziness and slurred speech for 1.5 years and numbness of both upper limbs for 4 months. After resting, he showed improvement and had intermittent attacks without any treatment. A computed tomography angiography (CTA) examination indicated stenosis at the beginning of the left internal carotid artery. Because of recurrent symptoms, he sought admission to our hospital for further treatment. Moreover, he had diabetes for 17 years and was treated with an orally administered antidiabetic medication. He also had hypertension for 10 months (blood pressure up to 220/120 mmHg) and was treated with an orally administered antihypertensive drug. He had 20-pack years of smoking history. Routine examination with CTA and DUS before surgery was performed. CTA indicated a small niche shadow in the left internal carotid artery on sagittal view, and no significant stenosis was found. The diagnosis based on CTA was atherosclerosis plaque surface ulceration. In the preoperative ultrasound examination, a membrane-like structure protruding into the lumen from the lateral posterior wall at the beginning of the left internal carotid artery on gray scale was noted, and an isoechoic plaque could be seen at the basilar part of the membrane-like structure. Moreover, the membrane-like structure projected into the lumen in a certain curve and was not floating in the blood. We adjusted the scanning angle for a better view of the whole length of the membrane-like structure; we observed a huge hollow space between the membrane-like structure and the plaque, which was similar to a large ulcer; however, the plaque surface was smooth and flat. In addition, color Doppler flow image (CDFI) showed a whirlpool at the level of the carotid web, and superb micro vascular imaging (SMI) demonstrated a membrane-like filling defect with a small, broad base in the longitudinal and transverse views. A diagnosis of a carotid web with an atherosclerotic plaque was made based on the aforementioned image characteristics. Furthermore, spectral Doppler imaging was performed on an ultrasonic imaging system (TOSHIBA Aplio™ 500, Japan) equipped with a linear array transducer (11 L-4 probe) at the carotid preset (frequency = 8 MHz, wall filter = 5). To relieve the symptoms of our patient, CEA was performed. The diagnosis of a carotid web with an atherosclerotic plaque by DUS was confirmed by the postoperative specimen; both the carotid web and the plaque surface were smooth without evidence of ulceration, which was consistent with the findings of DUS. The lesion tissue after CEA was fixed in formalin, embedded in paraffin, and sectioned in the axial plane. Sections were stained for hematoxylin and eosin, and the postoperative gross specimen and histopathology showed that the basilar part of the carotid web contained an atherosclerosis plaque. The carotid web consisted of extensive intima fibroid hyperplasia with myxoid degeneration; moreover, no ulceration was found in any of the sections. Subsequently, we performed CTA multiplanar reconstruction, and the membrane-like filling defect was best shown in both the sagittal and axial views; however, the atherosclerosis plaque attached to the carotid web could not be observed clearly. Our patient’s neurologic status continued to improve postoperatively.