What Is a Neck Aneurysm? Symptoms, Causes, and Treatment

A neck aneurysm is an abnormal bulge or dilation in one of the blood vessels running through the neck, most commonly a carotid artery or, less often, a vertebral artery or jugular vein. These aneurysms are uncommon compared with those in the aorta or brain, but they carry serious risks including stroke, compression of nearby structures, and rupture. The way they form, the symptoms they cause, and how doctors treat them depend heavily on which vessel is involved and what caused the weakening in the first place.

True Aneurysms and Pseudoaneurysms

Not every bulge in a neck artery is the same kind of problem. In a true aneurysm, all three layers of the artery wall (the inner lining, the muscular middle layer, and the tough outer sheath) remain intact but stretch outward, forming a balloon-like dilation. In a pseudoaneurysm, there is a full-thickness tear through the vessel wall, and the blood that leaks out is held in place only by the outermost layer or by surrounding tissue. The distinction matters because pseudoaneurysms tend to be less structurally stable and more likely to expand or rupture quickly.¹

In clinical practice, pseudoaneurysms of the neck arteries are actually more frequently encountered than true aneurysms. A literature review of cases treated with endovascular stenting found that only five of the reported cases involved true carotid aneurysms, with pseudoaneurysms making up the bulk of the rest.² This matters for patients because the underlying cause and the urgency of treatment often differ between the two types.

Which Blood Vessels Are Affected

The neck contains several major blood vessels, and aneurysms can develop in any of them, though some locations are far more common than others.

The carotid arteries are the vessels most often involved. You have a common carotid artery on each side of the neck, and each one splits into an internal carotid (which supplies the brain) and an external carotid (which supplies the face and scalp). Aneurysms can form at any point along these branches. A study of patients with penetrating neck injuries found pseudoaneurysms in the internal carotid, external carotid branches, and vertebral artery, with the external carotid branches being the most frequent site in that trauma population.³

Vertebral artery aneurysms in the neck are rarer. In inflammatory conditions like Takayasu arteritis, the carotid artery is involved in roughly 40 to 80 percent of cases, while the vertebral artery is involved in about 19 percent, and cervical vertebral artery aneurysms specifically remain unusual.⁴

The jugular veins can also develop aneurysms, though this is an entirely different situation from arterial aneurysms. Jugular venous aneurysms are uncommon and most often involve the internal jugular vein.⁵ Because veins carry blood at much lower pressure than arteries, venous aneurysms generally pose fewer immediate dangers and are managed differently.

What Causes a Neck Aneurysm

The causes fall into several broad categories, and the type of aneurysm (true vs. pseudo) often lines up with the underlying cause.

Trauma

Injury to the neck is the single most common reason for carotid pseudoaneurysms. This includes penetrating wounds like stabbings or gunshot injuries, blunt force trauma such as car accidents, and iatrogenic injuries from medical procedures like central line placement or neck surgery. In one surgical series, the most common causes were penetrating trauma (four patients), iatrogenic injury (two patients), and blunt trauma (one patient).⁶ Even seemingly minor procedures or injuries to the neck can damage an artery wall enough for a pseudoaneurysm to develop days or weeks later.

Infection

Infected (sometimes called mycotic) aneurysms form when bacteria seed the artery wall and weaken it from within. Staphylococcus aureus is the most frequent culprit, though other organisms including Salmonella can also be responsible.⁷ Infections don’t have to start in the artery itself. A severe ear infection, for example, can spread to the tissues surrounding the carotid artery in the neck and damage the vessel wall enough to produce an aneurysm.⁸ Infected aneurysms are particularly dangerous because the arterial wall is actively being destroyed by the infectious process, making rupture more likely.

Connective Tissue Disorders

Certain genetic conditions make arterial walls inherently fragile. Vascular Ehlers-Danlos syndrome (type IV) is among the most significant of these. It is caused by a genetic variant affecting type III collagen production, and the resulting weakness in vessel walls predisposes affected individuals to spontaneous aneurysms, dissections, and rupture throughout the body, including the neck arteries.⁹ Other connective tissue conditions like Marfan syndrome and fibromuscular dysplasia can also contribute, though they are more frequently associated with aneurysms in other locations.

Vasculitis and Inflammatory Disease

Conditions that cause chronic inflammation of blood vessel walls can weaken them over time. Takayasu arteritis is a classic example, affecting the aorta and its major branches including the carotid and vertebral arteries.⁴ In children, Kawasaki disease can produce systemic arterial aneurysms, including in the neck vessels, as demonstrated in a case involving an infant who developed multiple aneurysms alongside the more commonly recognized coronary artery involvement.¹⁰

Radiation and Cancer Treatment

Radiation therapy directed at the head and neck region can damage arterial walls months or even years after treatment ends. This delayed weakening can lead to pseudoaneurysm formation, and in severe cases, to carotid blowout syndrome, which is a rupture of the carotid artery. In reported cases, patients developed carotid pseudoaneurysms roughly 11 to 12 months after completing radiation therapy, presenting with sudden massive bleeding.¹¹ Radiation weakens all layers of the vessel wall gradually, so these pseudoaneurysms can appear without warning long after the cancer itself has been treated.¹²

Additional causes include atherosclerosis (the buildup of fatty plaques that weakens and stiffens artery walls over time) and, rarely, idiopathic cases where no clear cause is identified.¹³

Symptoms and Warning Signs

The symptoms of a neck aneurysm depend on its size, location, and whether it is causing clots to form inside it. Many small aneurysms produce no symptoms at all and are found incidentally during imaging for something else. When symptoms do appear, they generally fall into two categories: compression of neighboring structures and problems caused by blood clots forming inside the aneurysm and traveling to the brain.

A pulsatile lump in the neck is the most recognizable sign. You or your doctor might notice a mass on one side of the neck that throbs in time with your heartbeat. Extracranial internal carotid artery aneurysms are rare and may present with these compressive or thromboembolic symptoms, sometimes both.¹⁴

When an aneurysm grows large enough, it can push against the structures packed tightly alongside the blood vessels in the neck. A giant external carotid aneurysm in one reported case compressed the esophagus and displaced the trachea, causing difficulty swallowing and breathing so severe that the patient could only sleep on one side to keep the mass from blocking his airway.⁵ Other compressive symptoms can include hoarseness (from pressure on the nerve controlling the vocal cords) and ear pain or fullness.

The neurological symptoms can be especially alarming. Aneurysms near the base of the skull or within the cavernous sinus (a venous channel just behind the eye) can compress cranial nerves, producing combinations of symptoms like a drooping eyelid, a constricted pupil, and double vision. One recognized pattern involves sixth nerve palsy (inability to move the eye outward) combined with Horner’s syndrome (a drooping eyelid and small pupil on the same side), caused by an aneurysm pressing on both the nerve controlling outward eye movement and the sympathetic nerve fibers running along the carotid artery.¹⁵¹⁶

Perhaps the most dangerous presentation involves stroke symptoms: sudden weakness on one side of the body, slurred speech, or vision loss. Blood clots can form in the stagnant blood pool inside the aneurysm, break off, and travel up to the brain. A transient ischemic attack (a brief episode of stroke-like symptoms that resolves on its own) can be the first warning that a neck aneurysm exists, and it should always be taken seriously as a sign of potential stroke risk.

How Neck Aneurysms Are Found

Because neck aneurysms are rare and their symptoms overlap with many other conditions, diagnosis often involves multiple imaging steps. A pulsatile mass in the neck can be mistaken for an enlarged lymph node, a salivary gland tumor, or a carotid body tumor, so imaging is essential to tell these apart.

Doppler ultrasound is often the first test. It is noninvasive, widely available, and can show blood flow patterns inside a mass, which helps distinguish a blood-filled aneurysm from a solid tumor. For pseudoaneurysms specifically, ultrasound can reveal the characteristic swirling flow pattern inside the false sac. Multidetector CT angiography (a type of CT scan with contrast dye that creates detailed images of the blood vessels) can then confirm the diagnosis with enough clarity that traditional catheter-based angiography is often unnecessary.¹⁷ CT angiography provides three-dimensional reconstructions that help surgeons plan their approach, showing exactly where the aneurysm starts and ends and how it relates to nearby structures.

MR angiography (using an MRI scanner rather than X-rays) is another option, particularly when radiation exposure needs to be limited or when the aneurysm is close to the skull base. In practice, CT angiography tends to be faster and more widely available in emergency settings, while MR angiography may be preferred for follow-up imaging or in younger patients.

Treatment Options

Treatment depends on the aneurysm’s size, location, type, symptoms, and the patient’s overall health. The overarching goals are to prevent rupture and stroke while maintaining blood flow to the brain.

Open Surgical Repair

Traditional open surgery remains the established approach for many neck aneurysms. The surgeon exposes the affected artery through an incision in the neck, controls blood flow above and below the aneurysm, and then repairs or replaces the damaged section. A review of 220 open repairs found that the most common techniques were graft interposition (replacing the aneurysm segment with a vein or synthetic tube, used in about 35 percent of cases), end-to-end reconnection of the artery (about 29 percent), and patch repair (about 22 percent).¹⁸ In some cases, a vein graft harvested from the patient’s own leg is used to reconstruct the artery.¹⁹

Open surgery gives the surgeon direct control and the ability to handle complex anatomy, but it comes with risks. The many nerves running through the neck (controlling swallowing, voice, tongue movement, and facial sensation) can be injured during the operation, and the procedure requires clamping the carotid artery temporarily, which means the brain’s blood supply is interrupted for a period.

Endovascular Repair

The less invasive alternative involves threading a catheter from an artery in the groin up into the neck, then placing a covered stent (a mesh tube lined with fabric) inside the aneurysm to seal it off from the inside. This approach avoids a neck incision entirely, can be performed under local anesthesia, and eliminates the risk of cranial nerve injury that comes with open surgery. A review of reported stenting cases found a graft patency rate of about 93 percent.²

Endovascular repair is not suitable for every patient. Aneurysms with complex shapes, those located at the very top of the neck near the skull base, or those associated with active infection may still require open surgery. The long-term durability of covered stents in the carotid artery is also less well established than open repair, partly because the condition is so rare that large comparative trials have not been conducted.

Bypass Surgery

For aneurysms in locations where neither direct repair nor stenting is feasible, surgeons can reroute blood flow around the problem entirely. In one reported approach, the internal carotid artery was closed off and a graft from the external carotid artery was connected to a branch of the middle cerebral artery inside the skull, creating a new pathway for blood to reach the brain and achieving a good outcome.²⁰ This kind of surgery is complex and reserved for situations where simpler options are not possible.

Observation

Not every neck aneurysm requires immediate intervention. Small, asymptomatic aneurysms may be monitored with periodic imaging. Jugular venous aneurysms, in particular, are typically benign and may be managed conservatively depending on symptoms, the aneurysm’s shape, and the fragility of the vessel wall. In one reported case, a patient with an incidental internal jugular venous aneurysm was managed without surgery because symptoms resolved once an underlying anemia was corrected.²¹

The Risk of Doing Nothing

For arterial aneurysms in the neck, the natural tendency is to grow over time, and growth increases the risk of both clot formation and rupture. Even aneurysms in locations thought to be relatively “protected” carry real danger. Cavernous carotid artery aneurysms, which sit inside a bony compartment at the base of the skull, were once considered low-risk because the surrounding bone was thought to contain any rupture. But evidence shows these aneurysms can erode through bone and rupture, with a hemorrhagic event rate of roughly 0.5 per 100 person-years of follow-up.²²²³ That number sounds small in any given year, but it compounds over time, which is why many specialists lean toward treatment for growing or symptomatic aneurysms.

Infected aneurysms carry the highest urgency. The combination of an active infection destroying the vessel wall and pulsatile blood pressure pushing outward makes rupture far more likely than in other types, and infected carotid artery aneurysms are described as life-threatening.⁷ These typically require both antibiotics and surgical treatment rather than one or the other.

When a Neck Mass Might Not Be an Aneurysm

A lump in the neck has a long list of possible explanations, and aneurysms are far down that list in terms of frequency. Enlarged lymph nodes, thyroid nodules, salivary gland tumors, and cysts are all vastly more common. Among vascular masses specifically, a carotid body tumor (a slow-growing growth at the point where the common carotid artery splits) can mimic the appearance and location of a carotid aneurysm. Carotid body tumors also sit at the carotid bifurcation and may pulsate, but they are solid masses rather than blood-filled sacs, and they move side to side but not up and down when pressed. Imaging with CT angiography or MR angiography reliably distinguishes between the two.

Pseudoaneurysms of external carotid branches can sometimes present as a mass near the ear or jaw that resembles an enlarged parotid gland or a parotid tumor, especially after trauma. One case report described an external carotid pseudoaneurysm that presented as an atypical parotid mass following a penetrating injury.¹³ The key lesson is that any new, pulsatile, or rapidly growing mass in the neck deserves imaging, especially if there is a history of trauma, surgery, radiation, or known vascular disease.

Neck Aneurysms in Children

Most neck aneurysms occur in adults, but they can appear in children under specific circumstances. Kawasaki disease, an inflammatory condition that primarily affects children under five, is best known for causing coronary artery aneurysms, but it can also produce aneurysms in the systemic arteries, including the neck. A reported case involved an infant who developed neck swelling along with fever and was ultimately diagnosed with Kawasaki disease and multiple systemic arterial aneurysms.¹⁰ Connective tissue disorders like vascular Ehlers-Danlos syndrome can also present with aneurysms at a young age. In children, the threshold for investigation of a neck mass is generally lower, and any pulsatile swelling should prompt vascular imaging.

Trauma-related pseudoaneurysms are rare in children but not unheard of, particularly after high-energy mechanisms like motor vehicle accidents. The principles of treatment are the same as in adults, though surgeons tend to favor techniques that preserve future growth potential of the vessels.

1
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2
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3
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4
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8
PubMed Central. Mycotic Aneurysm of the Extracranial Internal Carotid Artery Following Otitis Media
9
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10
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11
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12
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13
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14
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15
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16
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17
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