just what type of test did he have that actually found this? did the report mention anything about any type of possible cystic type of disease going on there or was this just a 'mass" listed as a finding in his report? what did his referring doc say about this and who is he sending him to to have this better defined? it could be many different things that are just possible to pop up in any given abdominal organ. it will probably take some better more in depth testing(perhaps a biopsy even) to really be able to actually tell what this consists of. that is what he needs to really find out, what that mass consists of.
there is a really great kidney board here on this site just a scroll on down in the "K" section. i do hope this is more of a cystic thing than something else. please keep me posted. FB