I know exactly how difficult your decision was dealing with that level of processing for almost 5 years. The best case scenario for me, before it disappeared completely, was that often they felt it was simply scar tissue from an initial mass that they bladed between chemotherapy and radiation. Again that biopsy Did not determine any malignancy at all. I’m glad that at least the last scan disappeared, that’s a mixed blessing as well. Scar tissue, a really benign condition, doesn’t just disappear so the best case scenario of scar tissue has gone away. I’m able to access Medical information readily and it seems that around 2% of masses like this on kidneys will “disappear “from a scan at some point, sometimes they return sometimes they don’t. I know with each scan I had when I would talk to the urologist we would have the discussion about , should it be removed or should it continue to be watched and because the size of mine about the same and remained really small we always opted for let it be. When it started to change, it didn’t get any bigger, but it started to look like a bubbled up mass that was worrisome. The crazy thing just vanished last year! I have another scan in about six months and we’ll see what it looks like. But there’s no easy answer and there’s no 100% accuracy with any biopsy report. What seemed maybe the most definitive bit of information for me was that I had absolutely no symptoms of kidney disease or kidney issues. my kidney function was and remains perfectly normal. I have no symptoms at all. What I have learned is that those kidney masses can just drive you nuts. Everyone patients and doctors included, do the very best they can to make the very best judgment call. I hope your stay gone forever!