A venous aneurysm is a localized lesion in the venous system, the veins that carry blood to the heart. These aneurysms are typically found in the lower extremities, most often involving the popliteal vein, which carries blood from the knee joint through the thigh. The abdominal and thoracic veins can also be affected, as well as areas of the head and neck. A venous aneurysm is not as common as an arterial aneurysm, which is a bulge that occurs in the walls of the arteries.
While arterial aneurysms are more common, venous aneurysms do occur, and can be found in people of any age. Aneurysms are classified by size and shape, and may be referred to as either saccular or fusiform. The shape and size of a venous aneurysm will have some bearing on whether surgery is required to correct it.
Venous aneurysms of the neck and face, while rare, are usually congenital conditions. They often show up as small masses which protrude slightly from the affected area. The jugular vein is the most common site for venous aneurysms within the neck. The majority are benign and don't typically result in any significant health threats. They account for nearly one-third of all venous aneurysms, and surgery is usually performed purely for cosmetic reasons.
Abdominal venous aneurysms can occur anywhere within the venous system of the abdomen. One of the most common sites is the portal vein, which transports blood to the liver via the intestines and pancreas. Portal vein aneurysms can be a health concern, and a patient may have symptoms such as gastrointestinal bleeding.
Thoracic venous aneurysms occur in the thorax, the area between the neck and the abdomen. They are commonly seen in older individuals, and while they are usually asymptomatic, a patient will sometimes complain of chest pain. Abdominal and thoracic aneurysms can be detected by both magnetic resonance imaging (MRI) and x-ray computed tomography (CT), and a physician may recommend surgery.
Popliteal venous aneurysms (PVAs) can have more profound effects, often resulting in pulmonary embolism, an obstruction of the blood vessels in the lungs, which can lead to death. This type of venous aneurysm usually requires surgery, particularly if it is sizeable. PVAs may be detected due to pain and swelling behind the knee, but they are often asymptomatic. As with other forms of venous aneurysms, PVAs are extremely rare, and are most likely the cause of congenital venous malformations.