Morphology and immunohistochemistry of ccpRCC. (A) On histology, ccpRCC exhibits a papillary architecture under low magnification (HE, ×40); (B) under higher magnification, the tumor shows cells with clear cytoplasm with luminally oriented low grade nuclei, away from the basement membrane (HE, ×200); (C) by immunohistochemistry, ccpRCC shows strong membranous staining for CK7 (×200); (D) strong “cup shaped” staining for CA-IX with characteristic absence of staining along the lumen (×200). ccpRCC, clear cell papillary renal cell carcinoma; CA-IX, carbonic anhydrase IX.