We describe a case of a 78-year-old man who presented with a mycotic a
neurysm of the thoracic aorta caused by Clostridium septicum and under
went successful resection. There are only 3 cases of mycotic aneurysms
caused by Clostridium septicum reported in the literature. Clostridiu
m septicum infections have been shown to have a high association with
gastrointestinal and hematologic malignancies. AII patients with Clost
ridium septicum infections, therefore, require a search for gastrointe
stinal lesions, as they may represent a source of persistent bacteremi
a. This patient had no malignant lesions but did have multiple benign
sigmoid polyps.