The picture shows a Mesaortitis luica, which is an inflammation that mostly affects the thoracic aorta, or rather the vasa vasorum in its adventitia (tiny vessels inside the vascular wall of bigger vessels).
This form of vascular disease mostly occurrs in the tertiary stage of syphilis and leads to cicatricial changes of the tunica media. Complications can be aneurysms or vascular ruptures.
