Retroperitoneal undifferentiated pleomorphic sarcoma with aortic and inferior vena cava involvement presenting as right common iliac artery rupture

Retroperitoneal sarcomas rarely invade major vessels, with arterial rupture as a presenting symptom being exceptionally uncommon. Retroperitoneal undifferentiated pleomorphic sarcoma presenting with right common iliac artery rupture and inferior vena cava thrombosis is described. A 46-year-old female presented with right common iliac artery rupture requiring emergency endovascular aneurysm repair. Further workup revealed retroperitoneal sarcoma invading the inferior vena cava and bilateral common iliac veins. En bloc tumor resection with vascular reconstruction was performed, including right renal vein reconstruction using autologous superficial femoral vein and aortobifemoral bypass with prosthetic graft. Undifferentiated pleomorphic sarcoma was confirmed histopathologically. This exceptionally rare presentation was completely resected.