Contained chronic rupture of aortic aneurysm (CCR-AA) is a rare condition that can be associated with vertebral body erosion (VBE) and is often a diagnostic challenge; in fact, CCR-AAs are in general hemodynamically stable and the patients tend to present with a non-specific low-back pain syndrome secondary to vertebral involvement. Furthermore, the differential diagnosis of a retroperitoneal mass can be difficult on medical imaging. We discuss the case of a 79-years-old man, heavy smoker without history of cardiovascular diseases, admitted to the emergency department with signs of left lower limb ischemia. The patient was hemodynamically stable and the medical examination revealed a pulsatile abdominal mass. Doppler ultrasound showed the presence of aneurysmal dilatation of infra-renal abdominal aorta and chronic femoropopliteal occlusion on the left side. The subsequent computed tomography angiography (CTA) demonstrated a voluminous retroperitoneal mass continuous with the infra-renal aorta, which infiltrated the psoas muscles and caused vertebral bodies erosion of the anterior wall in L2, L3 and L4 suspected for CCR-AA or mycotic aortic aneurysm. Furthermore, the examination confirmed the occlusion of the peripheral arterial circulation of the left lower limb. The patient underwent a successful open replacement of the infra-renal abdominal aorta through aorto-aortic prosthetic graft insertion; the visualization during the surgical procedure of a posterior vessel wall opening in continuity with the eroded vertebral bodies associated with negative microbiological culture of the thrombotic material sample, led to the definitive diagnosis of CCR-AA. The post-operative CTA showed successful open vascular treatment. A bypass surgery of the left lower limb was then performed with positioning saphenous graft between femoral common artery and posterior tibial artery. The patient was finally discharged in good clinical conditions.