KRT7 and neoplasm: Immunohistochemistry showed tumour cells positive for cluster of differentiation 10 (CD 10) and α-methylacyl CoA racemase (AMACR) (Fig. 4) and only focally positive for cytokeratin 7 (CK7) (Fig. 5), which excluded clear cell papillary renal cell carcinoma (World Health Organization grading system 2017) in the differential diagnosis.