Mr. Ansari, a 48-year-old diabetic and hypertensive man from Birgunj, Parsa, presented with a three month history of a right-sided abdominal lump and 15 days of vague right abdominal pain and fullness. On examination, a 20x20cm soft to firm mass was found in his right lumbar region that was mobile laterally but fixed posteriorly and non-painful. Imaging showed a large retroperitoneal mass. Exploratory laparotomy revealed a 20x20cm retroperitoneal mass adherent to nearby structures but without invasion, appearing lipomatous with central necrosis. The diagnosis was a retroperitoneal mass, possibly a liposarcoma or angiomyolipoma