Rapidly Progressive Necrotizing Aortitis Due to Clostridium Septicum: A Rare Event

We present rapidly progressive necrotizing aortitis caused by Clostridium septicum in a 52-year-old male with no significant medical history. The patient was initially presented with nonspecific symptoms, including chest pain and mild abdominal discomfort, and was initially diagnosed with pericarditis. Within days, he developed a mycotic pseudoaneurysm of the ascending aorta extending in the descending aorta, requiring emergent surgery. Subsequent blood cultures identified Clostridium septicum , prompting further evaluation that revealed an underlying invasive colon adenocarcinoma. This case underscores the importance of considering rare infectious causes in acute aortitis and the critical link between Clostridium septicum bacteremia and gastrointestinal malignancies.