An infrequent case of isolated right internal iliac artery aneurysm rupture in an 86-years old high-risk patient is reported here. The rupture was initially misdiagnosed, thus the patient developed a giant pseudoaneurysm that filled the pelvic cavity, inducing sciatic nerve compression symptoms and poor general condition. Due to the age and the associated co-morbidities of the patient and the anatomical location and complexity of the aneurysm, we decided to perform a percutaneous endovascular treatment. The presence of an ectatic common iliac artery without associated aorto-iliac aneurysm represented an issue that required careful planning and sizing evaluation. The intervention consisted of three steps: 1) coil-embolizarion of the internal iliac artery side-branches to avoid back-filling of the aneurysm; 2) coil-embolization and Onyx 18 and 34 Liquid Embolization System (TM) (Medtronic. Irvine, CA, USA) instillation inside both, the aneurysm and the pseudoaneurysm, to induce its total occlusion and 3) internal iliac artery coverage with a balloon-expandable covered stent for aneurysm exclusion. No postoperative complications occurred. Complete aneurysm and pseudoaneurysm exclusion with no signs of endoleaks were assessed on the computed tomography angiography scan at discharge and 5 months after the intervention. Conclusion: the endovascular approach was a successful minimally invasive therapy in an old frail patient with complex anatomy.