Mycotic aneurysm caused by Clostridium septicum in a patient with colorectal cancer.

A mycotic aneurysm caused by a Clostridium septicum is a rare infection and has a strong association with colorectal cancer. If left untreated, the mortality rate of the first 24 h is high. This case report discusses the optimal treatment of emergency surgery combined with antibiotic treatment to improve survival. We present a fatal case of a 71-year-old male with abscedation of a caecal carcinoma who shortly after developed a mycotic aneurysm of the infrarenal aorta as a result of a C. septicum infection.