What is another name for a pseudoaneurysm?

What Is a Pseudoaneurysm?

A pseudoaneurysm, often referred to as a “false aneurysm”, isn't quite the same as a true aneurysm, though the names are easily confused. While both involve weaknesses in an arterial wall, a pseudoaneurysm forms when there's a rupture or breach in the vessel—usually due to trauma, surgery, or infection—allowing blood to leak and pool outside the artery but still contained by surrounding tissue.

Unlike a true aneurysm, where all three layers of the artery wall (the intima, media, and adventitia) bulge outward, a pseudoaneurysm occurs when only the outer layer (the tunica adventitia) and surrounding tissues hold the escaping blood. The blood accumulates in a sac-like structure between the tunica media and tunica adventitia, creating a fragile pocket that pulses with each heartbeat. This makes it both dangerous and difficult to miss if symptoms arise.

Common causes include iatrogenic injuries—such as those from catheterization procedures—particularly in the femoral artery, but they can also result from blunt trauma or penetrating wounds. Symptoms might include localized pain, swelling, or a pulsating mass near the injury site. In some cases, there may be no obvious signs until complications like clot formation or rupture occur.

Diagnosis is typically confirmed with ultrasound, which clearly shows the characteristic "to-and-fro" blood flow in the neck of the pseudoaneurysm sac. Treatment varies depending on size and risk, ranging from ultrasound-guided compression to minimally invasive techniques like thrombin injection or surgical repair.

While rare, a pseudoaneurysm should never be overlooked. Left untreated, it can lead to serious complications, including massive hemorrhage. Recognizing it early—and understanding it as a “false” but no less serious counterpart to a true aneurysm—can make all the difference.