AIM: The Persistent Sciatic Artery (PSA) is a rare congenital anomaly due to missed involution of embryo-fetal sciatic artery, which is the main blood supply to lower limb during embryonic development until superficial femoral artery (SFA) is formed. The PSA is frequently related to complications in adults like aneurysm and embolism. Here we present a case in which the discovery of a complete PSA resulted limb saving. In case of oncologic or trauma surgery, when no other options are available, the PSA can help in management of reconstructive surgery. CASE REPORT: A case of PSA was discovered during management of a patient affected by a soft tissue sarcoma of the lower limb. Tumor resection needed the femoral neurovascular bundle demolition to ensure radical surgery and subsequent vascular reconstruction, which failed due to complications. RESULTS: Despite failure reconstruction, a misdiagnosed type IIa PSA, replacing the role of the SFA, saved the lower limb from ischemia and subsequent amputation. Functional reconstruction was thus achieved with almost total recovery of lower limb function. DISCUSSION AND CONCLUSIONS: In oncological and trauma surgery we recommend investigate the whole lower limb vascularization, from the pelvis to the foot, suspecting the PSA existence. Indeed, although it is always preferable to reconstruct the SFA system despite a complete PSA is present, due to its frequent complications, the PSA can represent a limb saving option.