Background: Only 1% of all aortoiliac aneurysms could be presented with isolated internal iliac artery aneurysms with an incidence of 0.1% in the general population. Patients are mostly asymptomatic, yet they can present with clinical presentations related to aneurysm size and adjacent anatomical structures. Case Presentation: We report the case of a 76-year-old male patient with ruptured isolated internal iliac artery aneurysm presenting as ecchymosis and severe thigh pain with redness and discoloration. The patient was known hypertensive, diabetic type 2, and had end-stage renal disease but was not on regular hemodialysis. The patient's vital signs and systemic and abdominal examination were unremarkable, further laboratory tests were also normal. There was no sign of surrounding cellulitis and all the peripheral pulses were intact and normal. Because of unclear diagnosis and repeated visits to the emergency department, the patient was admitted for further investigation to rule out malignancy. CT abdomen was conducted and it revealed a ruptured internal iliac artery aneurysm with an extension into the gluteal region. Conclusion: Early diagnosis of isolated internal iliac artery aneurysm is difficult, as it is more easily detected when it is expanded or ruptured, which significantly increases morbidity and mortality rates and determines poor prognosis. Therefore, there are diagnostic as well therapeutic challenges. Surgical ligation is known as the most common management approach; however, the endovascular approach has shown promising outcomes, even in cases of a ruptured aneurysms.

Keywords: Ruptured aneurysm, iliac artery, neurological symptoms, leg swelling, DVT, case report.