Avid FDG uptake in a rapidly enlarging common carotid artery mycotic aneurysm, mimicking lymphadenopathy

We present a case of mycotic pseudoaneurysm of the right common carotid artery, which demonstrated avid FDG uptake mimicking lymphomatous involvement on a non-contrast FDG-PET/CT scan. Within 6 days of initial presentation, the pseudoaneurysm enlarged rapidly and required emergent surgical repair. To the best of our knowledge, this is the first reported case both of a PET-positive non-aortic aneurysm and a rapidly enlarging common carotid artery pseudoaneurysm. This case highlights the importance of contrast administration with PET/CT and the heralding nature of FDG uptake in an aneurysm wall for impending aneurysm rupture.