Background: Papillary renal neoplasm with reversed polarity (PRNRP) is currently described as a histologic variant of papillary renal cell carcinoma in the WHO Classification of Tumours 2022. Morphologically, this tumour is composed of thinly branching papillae and low grade oncocytic tumour cells with nuclei aligned towards the apex of the cell. They show consistent positive expression of GATA-3, less extensive labelling for AMACR, and have recurrent KRAS mutations, all features which are different to typical papillary renal cell carcinoma.
Namjoshi et al. (Sun,) studied this question.