Although true extracranial carotid artery aneurysms (ECCAs) are uncommon, they may involve severe clinical presentations due to complications. Carotid artery aneurysms constitute less than 1% of all peripheral artery aneurysms. Aneurysms can be classified as true aneurysms and pseudoaneurysms. According to meta-analysis reports, the majority of carotid artery aneurysms are pseudoaneurysms^9,10). Arterial pseudoaneurysms are pulsatile, expandable masses, associated with swelling and pain. An encapsulated hematoma with pulsation which is located around arteries as well as related with the lumen of a ruptured vessel is defined as “pseudoaneurysm formation”. Aneurysmal sac and increase in vessel size are occured due to arterial blood pressure; however, this dilatation is not consisted of every vessel wall layers. They most commonly develop secondary to trauma to blood vessel and less commonly after surgeries such as carotid repair. Atherosclerosis may lead to pseudoaneurysm formation through a process involving weakening of the vessel wall eventually causing ulceration. True aneurysms are the localized permanent enlargement of the artery diameter, with integrity of all vascular layers. True aneurysms constitute less than 10% of ECCAs. Some cases may be asymptomatic. The most common local symptoms and signs are a pulsatile mass, murmur at auscultation and neck pain. They may be life-threatening with serious clinical entities such as rupture and stroke^1-3,5,6).

Atherosclerosis is the most common etiological factor especially for true aneurysms. Other etiological causes include Ehler-Danlos syndrome, fibromuscular dysplasia, local infections in the neck region, previous radiotherapy to the neck region and surgical trauma^2,3).

In this paper, we present two cases of true ECCAs with the chief complaints pulsatile mass and neck pain. We treated these cases with open surgical procedures. The aim of this study is to discuss these cases in light of recent literature information.

The definition of ECCAs in the literature is unclear. This is because dilatation of the carotid bulbus is sometimes evaluated as physiological. In other words, there is a fine line between the definitions of dilatation and aneurysm. The classic definition of aneurysm is an increase of less than 50% in the normal arterial diameter. Bulbus dilatation, however, is regarded as a greater than 200% increase in the diameter of the ICA or a greater than 150% increase in that of the common carotid artery⁵⁾.

The most common presentation is a neck mass. It may be painful. The pain is more often functional and mostly due to the tension of the dilated carotid arteries. It also triggers reflex muscle spasm as a result of excessive stress in the surrounding muscles. Inflammation in the carotid sheath can be another cause of pain. Neurological events such as stroke or transient ischemic attack caused by embolisms deriving from thrombus in the aneurysm may represent the first clinical findings. Dysphagia, voice restriction, earache extending to the neck, Horner’s syndrome and, rarely, bleeding in association with sac rupture may be seen due to compression of neighboring tissues^7-9).

The incidence of true ECCAs is generally described as less than 1% in series involving the entire carotid entry^4-11). Majority of ECCAs course silently. Manifestation of neurological symptoms, increase in size of the mass and cranial nerve dysfunction are common cause of seek for medical attention and treatment. The morphological classification of ECCAs is divided into five types, depending on the location of the aneurysm¹⁾. The surgical options vary depending on this classification. In type 1, the aneurysm is distal to the ICA. In type 2 it begins from the proximal ICA and extends toward the distal. In type 3, the aneurysm is in the carotid bifurcation. In type 4, it is located in the ICA and common carotid artery (CCA) as a long segment. In type 5, it is localized in the CCA. In the light of this classification, surgical options of aneurysmectomy+end-to-end anastomosis are generally applied in type 1, aneurysmectomy+ autologous vein or Dacron-graft interposition in type 2, aneurysmorrhaphy or patch plasty or aneurysmectomy+graft interposition in type 3, aneurysmectomy+autologous vein interposition+external carotid artery re-anastomosis in type 4 and aneurysmectomy+graft interposition in type 5¹⁾. Both our cases were type 1 and both were treated with aneurysmectomy+end-to-end anastomosis. Our cases may also be described as ‘giant’ in terms of their size and location.

Alternative treatments for ECCA have been reported with endovascular techniques in some recent publications. Considering the limited success rate of conventional methods (open surgery) for the treatment of ECCA it is obvious that there is a need for more effective techniques to be implemented. For this regard endovascular techniques offer opitimistic alternative especially in cases with previous neck surgery, hostile neck conditions casued by interventions such as radiotherapy. Endovascular intervention was performed in 12.8% of cases in Mayo Clinic’s series. All of these cases were pseudoaneurysms, but not true aneurysms⁶⁾. Main factors affecting the choice between open surgery and endovascular intervention are aneurysm type and localization⁹⁾. Due to the idea of pseudoaneurysms as self-limiting, endovascular intervention may be an alternative treatment for this type of aneurysms^6,10). True ECCAs cases require endovascular instrument with bigger diameter and length. Endovascular interventions may also cause aneurysm degeneration due to regrowth or disease progression. Late complication, stroke and stent graft migration rates are increased in these patients⁸⁾. In addition, endovascular treatment can not relieve compression-related symptoms because existing aneurysmal sac still cause mass effect. Long-term results of endovascular intervention in these cases are still insufficient¹⁰⁾. For these reasons, endovascular interventions for patients with ECCAs may not be best treatment option. However, although this is a promising development, it has not yet become an alternative to open surgery^12,13). Surgical repair levels of 94%, endovascular treatment at 5% and hybrid treatment options at 1% have been reported in invasive therapies in case series¹²⁾. According to a recent review conservative management of ECCAs results in 4.67 % mortality and 6.67% stroke and invasive treatment reduced the rate of mortality to 1.91% and 5.16% stroke development. These levels suggest that surgery is superior to conservative treatment. Cranial nerve injury at a level of 11.8% has also been observed during open surgery therapy¹²⁾. Ligation is also a traditional therapeutic method in selected cases.

ECCAs are uncommon, but nevertheless represent a serious clinical condition in the light of potential complications. Open surgery is still the preferred therapeutic option.