Classification of renal epithelial neoplasms

Abstract

Advances in our understanding of the genetic abnormalities that lead to the development of renal carcinomas have led to the formulation of a new histopathological classification. This classification is based on these genetic changes but can be implemented by the use of conventional histopathological methods. The most common renal carcinoma is the conventional or clear cell type associated with a mutation in the Von Hippel Lindau (VHL) gene and with loss of chromosome 3p. Papillary carcinoma, chromophobe and collecting duct carcinomas have distinctive morphology and clinical behaviour and a different set of genetic alterations. Sarcomatoid transformation is now defined as a progression factor common to all of the variants of renal carcinomas rather than a separate entity. Some benign neoplasms are also recognised including oncocytoma, renal adenoma and metanephric adenoma. The morphology of these various renal epithelial tumours is discussed.