Rationale: We present a case of common carotid artery (CCA) diaphragm. To our knowledge, this is the first reported case in the imaging literature.
Patient concerns: A 33-year-old woman presented herself to an annual health examination without any report of ill health.
Diagnoses: A stenosis with aneurysm dilation on the proximal part of the right CCA was revealed on ultrasound and CTA, by which a diaphragm-like structure on the stenosis lesion was clearly identified. An anatomic variant of artery was first considered.
Interventions: The patient was followed up closely.
Outcomes: There was no progression of her CCA stonosis 1 year later.
Lessons: This unusual and previously unreported case is presented to alert vascular sonographers and radiologists to its existence.