Beyond the term penetrating aortic ulcer: A morphologic descriptor covering a constellation of entities with different prognoses

Penetrating aortic ulcer (AU) is defined as localized disruption of the intimal layer of the aortic wall, resulting in a crater-like lesion outpouching from the vessel contour. AU is a generic term which encompasses a constellation of entities with different etiologies and prognoses and may be a complication of infective, inflammatory, traumatic, iatrogenic, atherosclerotic processes or intramural hematoma. One of the most challenging scenarios of AU for a differential diagnosis, but also for treatment implications, is when they are associated with acute aortic syndrome. Despite advances in the field of aortic disease, lack of consensus defining these lesions and the significant semantic confusion in the medical literature of the acronym PAU (for penetrating aortic ulcer but also for penetrating atherosclerotic ulcer) have given rise to controversy in guidelines and expert consensus, leading to the same treatment being recommended for entities with different etiology and prognosis. Moreover, in the medical literature, most diagnoses were mainly based on imaging techniques which identified AU regardless of clinical symptoms, surrounding imaging findings or dynamic morphologic changes. In this Review, we provide the latest insight into the differential diagnosis between AU, also called penetrating aortic ulcers, based on clinical context and the newest imaging characteristics to aid treatment decision-making.