KRT20 and renal cell carcinoma: In response to a case scenario, 21 (33%) pathologists would label a renal tumor as unclassifiable if it showed a mixture of eosinophilic papillary and non-papillary morphology without cystic areas and diffuse positivity for keratin 20, in which FH and SDHB are retained/normal within the tumor cells; 32 (51%) respondents would categorize such a tumor as ESC RCC (Question #18).