How is grading of urothelial tumors?

• 2016 WHO Classification continues to recommend the 2004 WHO / ISUP Consensus Classification. • Low grade v/s High grade distinction : for non infiltrating and pT1 tumors • > 95% of (pT2-pT4) tumors are high grade. Exception: Nested variant • Grade the tumor according to the highest grade –%, if <10% comment