This was a tough one.

Although yes, you should ALWAYS think of a pseudoaneurysm when you see an abnormality of the aorta, don’t forget to use all images in all planes.

This patient had an outpouching extending medially towards (behind) the esophagus. If you look on the coronal you can see it has a somewhat beaked appearance with a small line of hyperdensity (contrast) extending up and to the patient’s right.

Answer: Kommerrell diverticulum at the origin of an aberrant right subclavian artery

Reference: https://radiopaedia.org/articles/kommerell-diverticulum