One patient was diagnosed with pT3a cN0M1, Fuhrman grade 3 CCPRCC with renal vein invasion and lung metastasis in 2010 on the basis of the histologic pattern and immunoreactivity for CK7.
Twenty-five cases were morphologically and immunophenotypically consistent with CCPRCC; all of them showed diffuse CK7 expression and cup-like reactivity with CAIX.
Diffuse labeling for CK7 can uncommonly be observed in clear cell renal cell carcinomas confirmed to have chromosome 3p loss, although these do not exhibit the expected staining pattern of clear cell papillary renal cell carcinoma, including positivity for CD10 and AMACR.