Abstract
Primary renal neoplasms comprise multiple distinct entities, some of which are well understood and others that are not. It is not uncommon for some of these entities to have overlapping morphologic features. Their clinical behavior is varied, ranging from highly malignant to benign, and metastatic renal cell carcinoma oftentimes enters into the differential diagnosis of tumors of unknown primary. In this age of personalized medicine, identifying biomarkers that can better predict clinical outcome and response to therapy is a pressing need. In 2013 the International Society of Urological Pathology held a meeting in which best practices recommendations on the use of immunohistochemical markers in urologic malignancies were discussed. In this review we make recommendations regarding immunohistochemical markers that are best suited to aid in establishing a diagnosis of renal primary, panels of antibodies that are most useful in classifying renal tumors, and the current status of prognostic and predictive biomarkers. Although no prognostic or predictive marker and set of markers have yet to be validated, ongoing research suggests that this fact is likely to change in the near future.