Dilatation of an artery as a result of damage to one or more layers of the arterial wall caused by trauma or aneurysm rupture; also known as a pulsatile hematoma is called

• A. Pseudoaneurysm
• B. Lymphocele
• C. Retroperitoneal Abscess
• D. Mycotic Aneurysm

Answer: (A)

When an artery is breached, blood escapes into surrounding tissue but remains connected to the artery, forming a hematoma that is bounded by tissues rather than by the vessel wall. This creates a pulsatile mass because arterial blood continually fills and empties through the arterial lumen. That communication and the contained hematoma define a pseudoaneurysm (false aneurysm). It commonly follows trauma or a vascular puncture and presents as a pulsatile lesion.

On ultrasound with Doppler, you’d expect a sac adjacent to the artery connected by a narrow neck; color Doppler may show a yin-yang appearance within the sac and spectral Doppler at the neck demonstrates to-and-fro flow, confirming ongoing communication with the artery.

Lymphocele is a lymphatic fluid collection without arterial communication, so it’s not pulsatile. A retroperitoneal abscess is an infectious fluid collection and generally lacks arterial communication. A mycotic aneurysm is an infected aneurysm of the arterial wall, typically a true aneurysm, not a pulsatile hematoma arising from a wall breach with a contained hematoma.