Ask your urologist what the Bosniak classification of the cyst is (check out the URL at the bottom of my post). Depending on what the classification is, he may decide to leave it alone. I read that something like 75% of humans have renal cysts and never even realize it (as their particular lesions don't cause pain/discomfort, aren't calcified, don't pose any significant threat/issue).
I had 4 large cysts on my left kidney (3-4cm's) along with about 100 smaller ones. I've had kidney problems for years (kidney-stones), and my urologist surmised that 19 years worth of x-rays, CT-scans, procedures, trauma, etc, did the trick. Exposing the kidney to a lifetime of crappiness, radiation, 200+ stone removal procedures, blah,blah, blah... my poor kidney subsequently became "cystified" (I made that word up... you like?!?).
My urologist performed a "Renal Cyst Decortication". Think of a cyst kind of like a blister. Little bubble with fluid in it, basically. Well, they go in, slice off the top, drain the fluid, and cauterize it to stop it from re-forming. Eazy, peezie, lemon-squeezy! 5 SMALL incisions for the laproscopy, 2.5hr procedure (I had a lot of lesions), and that's it. Now, I had numerous complications post-op, but it's because I just have crap luck, bad kidney problems and a lot of them, and I'm just an overall pain in the butt when I'm in the hospital!
Talk to your doctor about the Bosniak thing, then let me know what happened. Talk to you soon hopefully!
LMNO
URL: http://www.ctisus.com/multidetector/syllabus/BOSNIAK.html