Collateral anastomosis in Leriche syndrome complicated by presumed mycotic thoracoabdominal aneurysm.

Leriche syndrome can remain clinically silent when collateral pathways preserve lower-limb perfusion; however, coexistence with infectious aortic pathology poses a considerable diagnostic challenge for the radiologist. We report a rare case of a 49-year-old male who presented with acute back pain and dysphagia; CT imaging demonstrated a chronic aortoiliac occlusion alongside a suspected mycotic thoracoabdominal aortic aneurysm. Notably, perfusion of the lower limbs was entirely dependent on bilateral internal thoracic-epigastric collateral pathways. This unusual combination highlights the broad spectrum of vascular complications associated with intravenous drug abuse and thrombophilia.