I had almost similar experience. I fell on ice in December, got x-ray for my back pain, three weeks later I was sitting in a doctor's office getting a cancer diagnosis. Two cm is tiny! It doesn't seem like it. My tumor was 4.5 cm and that is considered early stage 1.
I thought I would lose the whole kidney besause of location, but after consulting with other surgeons in his office my dr decided they could save it especially since I was so young. (43)
Had the surgery 2/4/08 still having a long slow recovery but dr is confident cancer is gone and I still have 2 kidneys.
My prognosis is excellent dr said chance of normal life expectancy is over 90%.
Every one says I fell for a reason, I just thank goodness I had a radiologist that took his time reading a back x-ray.