Mycotic aneurysms of the ascending aorta in the absence of endocarditis.

Mycotic aneurysm formation is a rare and potentially fatal sequela of bacteremia. We present the cases of 2 octogenarians who had surgically confirmed mycotic aneurysms that involved the ascending aorta, with contained rupture (pseudoaneurysm). Neither patient had evidence of valvular endocarditis. Patient 1, an 82-year-old man, had streptococcal bacteremia. Imaging confirmed a mycotic aneurysm of the ascending aorta, and resection was successful. Patient 2, an 83-year-old woman, had recurrent staphylococcal bacteremia and progressive widening of the mediastinum, and imaging revealed a mycotic pseudoaneurysm. She underwent surgical repair with use of a bovine pericardial patch, but she died 2 weeks later because of patch dehiscence.We did not initially suspect mycotic aneurysm in either patient. Despite the availability of accurate, noninvasive imaging techniques, strong clinical suspicion is required for the early diagnosis of mycotic aneurysm.