We report a case of chronic rupture of the infra-renal aorta into the left psoas 6 years after implantation of an aorto-bifemoral prosthesis. There was no aneurysm nor false anastomotic aneurysm. The initially suspected diagnosis was acute sigmoiditis. We emphasize the polymorphous nature of clinical manifestations of chronic contained ruptures of the infra-renal aorta. Abdominal CT-scan is important for diagnosis. Strongly suspected, but not proven, sepsis led us to perform extra-anatomic revascularization after resection of the earlier prosthesis and ligature of the infra-renal aorta.