Idiopathic Pseudoaneurysm of External Carotid Artery with Delayed Facial Palsy After Covered Stenting

Background Idiopathic pseudoaneurysms of the external carotid artery (ECA) between the internal maxillary artery and the facial artery are rare. Endovascular covered stenting is an alternative method for surgically challenging cases; however, movable and flexible vessels may prevent the maintenance of the stent. Case Description A 26-year-old woman presented with sudden swelling and pain of the left chin due to a pseudoaneurysm of the proximal ECA trunk. She had undergone endovascular covered stenting and suddenly developed facial palsy at postprocedural 1 week. Regrowth of the aneurysm and slippage of the stent were detected, and additional stenting was performed. Swelling and pain of the chin and neck and subsequently the facial palsy completely resolved, and the patient made a full recovery. Conclusions The ECA aneurysm between the internal maxillary artery and facial artery may be more floating and changeable than any other portions of the ECA, and regrowth of the ECA aneurysm may cause delayed complication. In addition, knowledge of the mechanism is necessary to help in the endovascular treatment.