NIH stands for the USA's National Institutes of Health in Bethesda, MD. I believe that their pathology expert is at the Armed Forces Institute of Pathology. See
http://www.afip.org/Departments/Genitourinary/index.html and call for more information. Typically, they ask that you arrange for slides of your tumor to be sent from the hospitals where the biopsy and surgery were done, and the pathologist there re-examines the slides.
Also, some kidney tumors can be complex, composed of benign parts and malignant parts. You should get your pathology reports and see what the specific types of tumors are that were dianosed by your local pathologists.
All cancer treatment is based on the type of cancer as determined by the pathologist. I would get another opinion on both the biopsy and surgery slides.