[The WHO Classification of Renal Cell Tumours: Implications for Personalised Treatment Decisions and Accurate...

Renal cell carcinomas are among the most common malignant tumours of the urogenital tract. The current WHO classification of renal tumours comprises over 20 distinct subtypes, some of which have a specific molecular genetic background. The new WHO classification divides tumours into morphologically and molecularly defined tumours. In addition to the established subtypes - clear cell, papillary, and chromophobe renal cell carcinomas - new entities have been defined, such as eosinophilic solid and cystic renal cell carcinoma. The category of molecularly defined renal tumours includes renal cell carcinomas with TFE3 rearrangement, TFEB-altered renal cell carcinomas, ELOC-mutated renal cell carcinomas, fumarate hydratase-deficient renal cell carcinomas, succinate dehydrogenase-deficient renal cell carcinomas, renal cell carcinomas with ALK rearrangement, and SMARCB1-deficient medullary renal cell carcinomas. Based on recent findings of prolonged survival times and the absence of distant metastasis, several subtypes are no longer classified as carcinoma but as renal tumours, such as multilocular cystic renal tumours or clear cell papillary renal tumours. The WHO classification emphasizes the importance of genetically defined renal tumours, which are addressed in a dedicated chapter. Currently, molecular analyses guide treatment decisions in advanced cases following discussions in molecular tumour boards. Therefore, the classification of subtypes, together with their specific molecular alterations and signalling pathways, is gaining importance not only for targeted systemic therapy but also for the identification of patients with a hereditary tumour syndrome.The task of pathologists is to identify new tumour entities and genetically inherited tumour forms in order to ensure the best possible clinical care for patients.