The 2022 revision of the World Health Organization classification of tumors of the urinary system and male genital organs: advances and challenges

The fifth edition of the World Health Organization (WHO) classification of urinary and male genital organ tumors has been recently published in 2022. The application of molecular profiling has made a substantial impact on the classification of urologic tumors. The new WHO classification introduces a group of molecularly well-defined renal tumor subtypes. The significant changes include addition of a category of “other oncocytic tumors” with oncocytoma/chromophobe renal cell carcinoma (chRCC)-like features, elimination of the subcategorization of type 1/2 papillary RCC, and inclusion of eosinophilic solid and cystic RCC as an independent tumor entity. The WHO/ISUP grading now has been recommended for all RCCs. Major nomenclature changes include replacement of histologic “variants” by “subtypes,” “clear cell papillary renal cell carcinoma” to “clear cell renal cell tumor,” “TCEB1-mutated RCC” to “ELOC-mutated RCC,” “hereditary leiomyomatosis and renal cell carcinoma” to “fumarate hydratase-deficient RCC,” “RCC-Unclassified” to “RCC-NOS,” “primitive neuroectodermal tumor” to “embryonic neuroectodermal tumor,” “testicular carcinoid” to “testicular neuroendocrine tumor,” and “basal cell carcinoma of the prostate” to “adenoid-cystic (basal-cell) carcinoma of the prostate.” Metastatic, hematolymphoid, mesenchymal, melanocytic, soft tissue, and neuroendocrine tumors are collectively discussed in separate chapters. It has been suggested that the morphological classification of urothelial cancer be replaced with a new molecular taxonomic classification system.