Background <p>The carotid web is an established etiology of cryptogenic stroke, often implicated in younger patients without traditional risk factors. It is characterized radiologically by a distinct shelf-like projection into the carotid bulb without calcification and pathologically represents a form of fibromuscular dysplasia(FMD).</p> Case presentation <p>A patient presenting with acute cerebral infarction in the absence of traditional risk factors underwent brain magnetic resonance imaging (MRI), which revealed an acute infarction in the right middle cerebral artery (MCA) territory. Carotid ultrasound demonstrated a hyperechoic septum in the right carotid bulb with an associated floating thrombus. After 10 days of anticoagulation, the thrombus resolved completely. Subsequent computed tomography angiography (CTA) showed spontaneous recanalization of the right MCA occlusion, with no recurrent stroke during this period. The patient received 3 months of anticoagulation (rivaroxaban) followed by antiplatelet therapy (aspirin) and remained free of cerebral infarction recurrence during 16 months of follow-up.</p> Conclusions <p>Carotid web should be considered in the differential diagnosis of young patients presenting with acute ischemic stroke in the absence of conventional cerebrovascular risk factors. Thrombus formation adjacent to the web is a likely mechanism of cerebral infarction.</p>