Pathology of Urothelial Malignancies of the Upper Urinary Tract

Summary: The upper urinary tract includes renal pelvis and ureter which are muscular conduits lined by urothelium. The upper urinary tract may be involved by distinct entities which have different prognosis and diverse treatment options. Here, we focus on noninvasive urothelial carcinoma: low- and high-grade papillary UC, urothelial carcinoma in situ and noninvasive urothelial carcinoma with glandular differentiation; upper urinary tract urothelial carcinoma with intratubular spread; invasive urothelial carcinoma: different differentiation components and different variants; other non-urothelial malignancy: inflammatory myofibroblastic tumor, lymphoma, and rhabdoid tumor; Non-neoplastic tumor-like conditions: ureteropelvic junction (UPJ) obstruction and immunoglobulin G4-related kidney disease