Fig. 1

Histological characteristics of papillary renal neoplasm with reverse polarity. A Most of the tumors showed obvious intracystic papillary growth. B Transition zone between tumor tissue and renal tubular epithelia. C Tumors were primarily composed of papillary structures with complex branches and fibrovascular cores. D The tumor cells had abundant eosinophilic cytoplasm, with round nuclei far away from the basement membrane