Hello. Tumor showed up on my husband's scan which they too felt was renal cell. Sent immediately to have kidney removed as it had attached to it. Turned out not to be renal cell after they did surgery and biopsy. We have been told it is a sarcoma, which is rare and treatment options are very limited. We were immediately referred to Memorial Sloan Kettering in NY to a cancer specialist. He is getting ready for his 3rd surgery on the 16th.
If they arent' suspicious of your mass yet, I wouldn't wait till it gets bigger. Take the scans to a reputable cancer hospital.
Please feel free to ask me any other questions you might have and I will give you as much info as possible based on our experience.
Good luck
Sue