PAX8 and nonpapillary renal cell carcinoma: Although PAX8 has always been considered a reliable marker for distinguishing HB (PAX8-negative) from metastatic ccRCC (PAX8-positive), in the present study, about 40% of intracranial HBs from our series (9 out of 23) were stained, at least focally and weakly, with this antibody.