Mycotic pseudoaneurysm of the ascending aorta caused by Escherichia coli

Abstract

An 81-year old woman with high fever and a history of hospital admission because of pyelonephritis 3 months previously was transferred to our hospital. Contrast-enhanced computed tomography revealed a mycotic pseudoaneurysm in the ascending aorta and a massive pericardial effusion. We resected the ascending aorta and the proximal part of the brachiocephalic artery and performed in situ revascularization with a prosthetic vascular graft. Bacterial examination proved that the causative micro-organism was Escherichia coli. The prosthetic graft was wrapped with a pedicled omentum following completion of the aortic reconstruction. Her postoperative course was uneventful. She was discharged from the hospital 1 month postoperatively.

Figure 1:

Sagittal MPR image of contrast-enhanced computed tomography revealed a localized cystic protrusion adjacent to the brachiocephalic artery in the ascending aorta. Gas-like density spots surrounding the aneurysm were detected. Massive pericardial effusion was also identified. Ao: aorta, BCA: brachiocephalic artery, PA: pulmonary artery.

Figure 2:

Loupe image of the aortic wall revealed thickened intima consisting of collagenous tissue. Disruption of it is pointed by an arrow (a). Abscess formation is observed in the adventitia. Microscopic findings show infiltration of neutrophils and chronic inflammatory cells (b). Haematoxylin and Eosin stain. i: intima, ad: adventitia, ab: abscess.