Simply by thinking of the location of the pulsatile mass, one can identify the cause or causes of a pulsatile mass.
· Orbit. This is most likely an arteriovenous fistula related to trauma or the spontaneous rupture of an aneurysm into the cavernous sinus.
· Neck. A carotid, innominate, or brachial artery aneurysm is the most likely cause here, but pulsations may be felt in the neck from aortic regurgitation as well.
· Chest. An aneurysm of the thoracic aorta is the most likely cause here, but an enlarged heart or cardiac aneurysm may give a noticeable heave on inspection.
· Abdomen. Tricuspid regurgitation may cause pulsations of the liver in the right upper quadrant, but the associated ascites and dependent edema should make the diagnosis obvious. A pulsating abdominal aorta is usually an atherosclerotic aneurysm, but it may be an abnormal finding in asthenic individuals. It is also possible that the pulsating mass is a tumor over a normal abdominal aorta.
· Extremities. A pulsating mass in the axilla, groin, or popliteal fossa is usually an aneurysm, but osteosarcoma can produce a pulsating mass along with eggshell cracking.
Approach to the Diagnosis
Ultrasonography will usually confirm the diagnosis of these lesions, but a CT scan or angiography may be necessary, particularly when surgical intervention is planned. A cardiovascular surgeon should be consulted before ordering these expensive tests.