Pathology of the upper urinary tract tumours: Histologic subtypes, genetics, biomarker testing.

In the past few years, upper tract urothelial carcinoma (UTUC) has moved more towards the centre of interest in uro-oncology. Specific guidelines exist, and although these tumours are still rare, handling becomes more common, especially in centres specialized in this type of tumour. Most of the time, conventional urothelial carcinoma (UC) can be diagnosed, but subtypes of UC as well as other carcinoma types exist, which might be more complicated to report. These other tumour morphologies are rare, but recognizing them is of great importance. With the evolution towards personalized medicine, biomarkers have been found; some are evaluated on a protein level using immunohistochemistry, and some require molecular testing. This review will focus on which marker to take. Additionally, major efforts have been taken in order to characterize UTUC on a molecular basis, with some alterations encountered regularly, but others are less frequent. In order to progress with biomarker identification and hence potential new therapeutic options and personalized patient management, the underlying mechanisms must be understood in detail.