Acute Aortic Dissection Initially Suspected on 18F-FDG PET/CT.

A 64-year-old man with anal cancer underwent follow-up F-FDG PET/CT to evaluate chemoradiation therapy response 5 months after an initial PET/CT. The follow-up F-FDG PET/CT demonstrated new FDG-avid curvilinear soft tissue adjacent to the abdominal aorta, interpreted as an aortic dissection. Despite lack of clinical symptoms, the patient was directed to an emergency room the same day, where a contrast-enhanced CT confirmed an aortic aneurysm with dissection. The patient underwent endovascular surgical repair the following day. This case demonstrates that newly FDG-avid aortic soft tissue should be recognized and may need further evaluation to characterize clinically significant vascular pathology.