It means the lower L part of the kidney itself.if they did not mention the actual size of the cyst i really can't imagine that it is of any huge size.But all reports really should include some sort of a size reference if for nothing else a documented baseline size upon Dx.You stated that it is ON the kidney and not actually IN it/Or was that just the way you said it.I would really suprised if this most likely small cyst would be causing you alot of your pain.My kidneys are loaded with polycysts both inside and out and my pain did not start until my kidneys became quite large from all of the cystic development.It IS possible but i would say very unlikely.Your pain could be coming from some other place entirely and the cyst on the kidney is just purely an incidental find.I hope you find the source of your pain.I know, pain just sucks.marcia