Right large retroperitoneal complex cystic mass lesion is seen extending from the right hypochondrial region/hepatorenal pouch extends down into the right paracolic gutter retro-colic in location and reaches the right side of the pelvis. The lesion appears complex predominantly cystic showing enhancing internal septations which show tiny calcifications. The lesion is abutting the adjacent liver and right kidney. It invades the right psoas muscle. The lesion encases the patent right iliac vessels. In the pelvis, it compresses and displaces the urinary bladder to the left side. It also encases and compresses the right ureter with consequent marked right hydrouretronephrosis.
Gallbladder stones.
Radiological findings were suggestive of primary retroperitoneal tumor, such as myxoid liposarcoma or primary mucinous adenocarcinoma.