RESUMO
Retroperitoneal sarcoma is a rare tumor accounting for 10 - 15% of all soft tissue malignancies with an incidence of 2.5 per million. Of those, liposarcoma is the most common type of retroperitoneal sarcoma accounting for 41% of cases. It usually presents late with vague symptoms such as abdominal discomfort or palpable mass. Vascular invasion is seen in 18% of retroperitoneal sarcomas but acute renal failure secondary to bilateral renal artery invasion/stenosis by these tumors has never been described yet. In this report, we describe the first case, to our knowledge, in the medical literature and discuss epidemiology, diagnosis, and management. Treatment is primarily surgical and the ability to completely resect the tumor is the most important predictor of survival. Active clinical trials are currently testing the use of adjunct chemotherapy and radiotherapy to improve morbidity and mortality.