Intrathoracic infiltration of the inferior vena cava (IVC) is rare; mobilization and prosthetic replacement may increase the risk of cardiac arrest and postoperative complications. We report a case of a giant liposarcoma which elongated and grew around the IVC, invading both hemithoraces. The removal of this mass required a bypass between the left femoral and ipsilateral axillary vein to guarantee an adequate venous return. The IVC was replaced by a polytetrafluoroethylene prosthesis. A postoperative paralysis of patient's lower limbs occurred. Hypotension or involvement of aberrant medullary artery origin could be responsible for this complication.