Contrast-enhanced excretory computed tomography (CT) image of the abdomen at the level of the kidneys show a lobulated mass (arrow) in the retroperitoneum. The mass encases the abdominal aorta (A), inferior vena cava (V ), right and left renal arteries (RRA and LRA), and left renal vein (LRV ). The mass extends anteriorly into the root of the mesentery, encasing the head of the pancreas (P) and mesenteric vessels (arrowheads). The vessels appear to be floating within the mass. None of the involved vessels are obstructed. The visualized portions of the kidneys (asterisks) are well perfused and normal.