The majority of eosinophilic stratified (4/6; 67%) and eosinophilic papillary (12/14; 86%) cases were positive for CK7 and had variable staining for AMACR, CD10, or CAIX, suggesting a differentiation more aligned with papillary renal cell carcinoma.
However, because of a strong immunohistochemical labeling for alpha-methylacyl-CoA racemase, as well as the presence of a gain of chromosomes 7 and 17, we concluded that two of these tumors were actually pRCC.