Patient: Female, 53 years old, admitted to the hospital for: “pulsating mass in the left neck found for 1 month”. The patient had been seen at a local hospital 15 days earlier and was diagnosed with “possible left carotid aneurysm” by color ultrasound. On examination: heart rate was 68 beats/min, blood pressure was 142/82 mmHg, and a pulsating mass of 3 cm×4 cm in size was palpable on the left side of the neck against the lower jaw. After admission, MRA (Magnetic resonance angiography, Figure 1) and CTA (Computed tomography angiography, Figure 2) confirmed that the internal carotid artery was twisted, and the internal diameter of the twisted internal carotid artery was slightly thicker than the contralateral one, but within 150%. The magnetic resonance cranial scan did not show any significant abnormality. The patient was not given surgical treatment and was advised to take oral aspirin and come to our outpatient clinic for follow-up every six months after discharge. The patient’s medical history was not special, and the examination showed a pulsating mass on the left side of the neck, and the pulsation frequency of the mass was consistent with the heart rate. This presentation was very similar to that of carotid aneurysm, and it was difficult to differentiate it from physical examination. Together with the initial diagnosis of “carotid aneurysm possible” by color ultrasound from an outside hospital, it is very easy to misdiagnose as carotid aneurysm at this time. Internal carotid artery torsion is also easily confused with carotid body aneurysm, carotid artery pseudoaneurysm, carotid arteriovenous fistula and other vascular diseases of the neck. Carotid body aneurysms are located at the bifurcation of the carotid artery, and the arteriogram reveals a “cupped” separation of the internal and external carotid arteries with abundant blood flow. Carotid body aneurysms are closely associated with the carotid artery, so they are often palpable and pulsating. The most typical sign of carotid body aneurysm is Fontaine’s sign: the submandibular carotid mass is attached to the carotid bifurcation, so the mass can move perpendicularly to the carotid artery but not along it. Carotid body aneurysms are mostly painless on palpation, tough, tightly organized, and incompressible. The mass does not shrink after compression of the common carotid artery. Pseudoaneurysms of the carotid artery often appear as an elliptical mass near the carotid artery. The texture varies with the tension of the mass, and the local skin temperature is usually slightly higher than the surrounding area, but there is no redness, swelling, heat or pain. Pseudoaneurysms are often the result of post-traumatic neck injury and this information can be obtained by following the medical history. Carotid arteriovenous fistulas are usually heard as a distinct murmur on auscultation, and it is difficult to palpate a distinct mass. 2. Possible causes of carotid artery torsion: The most frequent bending of the carotid vessels are the common carotid, internal carotid and vertebral arteries, which are hyperflexed. It is often “transverse s” shaped and is associated with atherosclerosis in some patients. In a study by Li et al [2], 5 of 10 patients with carotid artery torsion had typical atherosclerosis. Some patients may be related to obesity, especially middle-aged women, and all 12 patients with carotid artery torsion studied by Zhang Lijun [3] were women. Because women are mainly thoracic breathers, and after middle age abdominal fat tends to accumulate, which can lead to a mild elevation of the diaphragm position, at the same time, the position of the cardiac great vessels after middle age will undergo a certain degree of transposition and mild elevation, which makes the great vessels in the neck to adapt to the changes in their physiological anatomical position and undergo an adaptive transformation DD twist. 3.Treatment of carotid artery distortion: For carotid artery aneurysm, 70% of those who are not actively treated surgically may suffer from intra-aneurysmal thrombosis and thrombus dislodgement causing cerebral blood supply deficiency or even cerebral infarction; or rupture of aneurysm to the pharynx, oral cavity, nose, etc. resulting in hemorrhage and death by asphyxiation. Therefore, carotid aneurysms are usually treated by carotid atherectomy and revascularization. 5%-7% of carotid aneurysms are malignant, while benign ones have a high malignancy rate; at the same time, the increasing aneurysms encircle the surrounding vascular tissues, which makes the operation much more difficult and dangerous, therefore, the principle of treatment for carotid aneurysms is early and complete surgical excision of the aneurysm [1]. In the case of carotid artery torsion, if the torsion is due to simple obesity, imaging confirms that there is no significant dilatation and there is no intravascular thrombosis, it can be treated as an outpatient follow-up. During the follow-up period, oral aspirin was administered to reduce the incidence of cerebrovascular events. In patients with obvious atherosclerotic occlusion, due to the change of direction, angle and pressure of distorted arterial blood flow, intravascular thrombus can be formed, and the thrombus can be dislodged and lead to infarction, so surgery can be given according to the patient’s will and comprehensive evaluation. The surgical approach is based on partial carotid resection with end-to-end anastomosis.