Abdominal CT scan reveals a left-sided well-defined multilocular cystic mass in the retroperitoneal space. It has homogeneous density and no post-contrast enhancement. The cystic lesion extends from the undersurface of the left diaphragm to the left iliac region, displaces the stomach, descending colon, and pancreas anteriorly without evidence of invasion. The bowel loops are pushed towards the right side. The left renal pedicle is completely encased, with no vascular compromise. The left kidney has smooth contour and normal contrast enhancement. Renal excretory phase CT shows no pelvicalyceal dilatation.