[Usefulness of the present renal cell carcinoma classifications]

The purpose of classifying neoplasias is to recognize groups with similar progress and prognosis and, if possible, receiving the same treatment. This is why those classifications are systematically being submitted to review and improvement through the new technologies. Differentiation of various entities in renal cancer has been comparatively fast, as the new genetic and molecular discoveries have confirmed the morphologic criteria of the different cell types, thus making it possible to open new therapeutic pathways. Using the current WHO classification we recognize subtypes with excellent prognosis (Multilocular cystic renal carcinoma, Type I renal papillary carcinoma, Tubular and fusocellular mucinous carcinoma), other very aggressive ones (Bellini's collecting duct carcinoma, Medullary carcinoma), and also that the sarcomatoid transformation, even in small areas, impacts the prognosis negatively. Childhood-characteristic renal carcinomas associated with chromosome translocations have been recognized (genetic fusion TFE3 or TFEB), as well as the family forms of renal carcinoma. Regarding the UICC (International Union Against Cancer) classification, there are a series of aspects under argument (size, venous invasion, microvascular invasion, invasion of the adipous tissue of the renal sinus) that shall be discussed too, since it is possible that some modifications of the TNM might occur in the near future.