A nine year old boy was brought with the history of pain in the abdomen since three months
Contrast enhanced CT scan of the abdomen shows a large. heterogeneous, multicystic lesion in the retroperitoneum centered in the right posterior pararenal space. It measures 12x10x20 cm with multiple chunky calcifications and osseous components. There are areas of macroscopic fat in the lesion. The cystic component shows thick peripheral wall enhancement with enhancing septae. Mass effect is seen on the adjacent structures. There is smooth scalloping and superior displacement of right lobe of liver. The right kidney is compressed and displaced antero-laterally.