Key clinical point: Clear cell papillary renal cell carcinoma (ccpRCC) is a recently recognized subtype of renal cell carcinoma with a unique staining pattern that can be used to distinguish this cancer. Further, vitamin D receptor-positive expression suggests that ccpRCC originates from the precursor epithelium of the distal nephron.

Major finding: Histopathologically, all 26 cases of ccpRCC exhibited a tubular and papillary architecture, covered by tumor cells with clear cytoplasm. Immunohistochemistry showed intermediate (5/26, 19%) to diffuse (21/26, 81%) and moderate (2/26, 8%) to strong (24/26, 92%) membranous staining for vitamin D receptor. All cases (26/26, 100%) were diffuse with strong cytoplasmic and fibrillar staining for cytokeratin 7 (CK7), but negative for α-methylacyl-CoA-racemase (AMACR). Each case showed diffuse (26/26, 100%) and moderate (4/26, 15%) to strong (22/26, 85%) membranous staining for carbonic anhydrase IX (CA IX). In addition, the majority of cases were negative for cluster of differentiation 10 (CD10) (20/26, 77%) and renal cell carcinoma maker (RCC-Ma) (24/26, 92%).

Study details: The clinicopathological and immunohistochemical features of ccpRCC were examined in 26 patients, mean age 53 years (range 36–74 years), with a mean tumor size of 2.5 cm (range 0.5 to 6.5 cm).

Disclosures: The authors had no relevant financial disclosures.

Source: Wang Y et al. Annals of Diagnostic Pathology 36: 2018; 1-4. https://doi.org/10.1016/j.anndiagpath.2018.06.007