Pathology of renal cell carcinoma: an update.

The use of classic and newer methodologies, including histopathology, electron microscopy, immunohistochemistry, cytogenetics, and molecular diagnostic techniques, has greatly influenced distinctions between various types of renal carcinoma. The most recent World Health Organization classification of renal neoplasms encompassed nearly 50 distinctive renal neoplasms. These categories have been expanded during recent years, incorporating newer histotypes, thus suggesting that the next revision of this classification will incorporate some of the recently recognized entities. In this review we examine the clinicopathologic and genetic features of renal carcinomas most often seen in clinical practice. Emphasis is placed on defining risk categories by incorporating pathologic predictive paradmeters and tumor histotypes. Since pathology of renal cell cancer is a rapidly evolving field, we also include brief comments on newer tumor variants for which there currently is not enough clinicopathologic information to permit classification as distinctive tumor histotypes.