I had to use a few images to get the whole abnormality on this one. It sounds like everyone narrowed it down to the right kidney (left is absent), but it is a pretty big kidney isn’t it? The key is that I tried to show 2 large clefts corresponding to hila. So yes, this is cross-fused renal ectopia.

http://radiopaedia.org/articles/cross-fused-renal-ectopia

This is similar to, but a different entity than a horseshoe kidney (http://radiopaedia.org/articles/horseshoe_kidney) where the kidneys are fused but remain on opposite sides of the patient.