2. (# 1 cont'd) • Patients with primary tumor in place are eligible if there is any percentage of sarcomatoid dedifferentiation on a needle biopsy (primary or metastasis), and the radiographic appearance of the primary tumor on CT scan is typical of RCC. For these patients, due to the small tumor sample, it is not required to identify an area of typical RCC histology as long as the morphologic and immunostaining characteristics are consistent with RCC.