This happened at least 15 or so years ago. It was actually discovered by my urologist at a time I believe he was looking at my bladder in the hospital. As I said, I spent most of my time with a radiologist who was an Interventionist. One of the ways to contain the growth of this small cancerous mass was to perform cryoblasia which essentially freezes this spot. All of this was performed in the hospital. Annually, I had an x ray for the first 5 years. No further growth took place during that time, so you may want to call it a cure as to my cancer, but know I have CKD, probably not related to this event. Medical treatment may have changed since then. Remember, I had one small mass on my right kidney, not multiple on both kidneys. I honestly do not know if it was identified as a "complex cyst". I had it done at Banner Hospital in AZ.. I really think your best bet is to work with your urologist and find a good interventional radiologist to help solve your problem.