The evolution of renal cell carcinoma classification

Precise classification of diseases is essential for precision medicine to develop efficient, personalized treatments for cancer. Progress in renal cell carcinoma (RCC) classification is a paradigm that demonstrates how precise classification is achieved. RCC classification has evolved from purely morphological criteria to the sophisticated application of various laboratory modalities. With advancing techniques and multi-institutional collaboration, the latest World Health Organization (WHO) classification takes into account decades of studies on the nature of RCC, and is subsequently divided into six categories: clear cell renal tumors, papillary renal tumors, oncocytic and chromophobe renal tumors, collecting duct tumors, other renal tumors, and molecularly defined renal carcinomas. This review provides a historical perspective on how the current WHO classification was attained, followed by a compendium of different RCC types and their salient characteristics, including histopathological features, clinicopathological correlations, and molecular distinctiveness. This information should be shared among pathologists and clinicians to better translate pathological findings into effective clinical practice in terms of diagnosis, prognostication, and therapeutic planning.