Primary urothelial carcinoma of the ureter without concurrent renal pelvic or bladder carcinoma: A contemporary clinicopathologic analysis.

Primary urothelial carcinoma (UCa) of the ureter is relatively uncommon, comprising less than 10% of all urinary tract tumors. Typically, ureteral UCa is found in association with other urinary tract tumors, such as renal pelvic or bladder UCa, making it challenging to analyze the clinicopathologic features in isolation. With only a few small case series and case reports available, our understanding of primary ureteral UCa is limited. Herein, we conducted one of the largest studies to date of primary ureteral UCa without concurrent renal pelvic or bladder UCa. Clinicopathologic parameters including extent of invasion, lymphovascular invasion, variant histology, presence of UCa in situ, inverted growth pattern, and clinical follow-up information were obtained. Ninety-seven cases were included in the study. Thirty-nine cases (40%) showed invasion, the preponderance of which invaded lamina propria (15%; 15/97), followed by periureteral soft tissue/adipose (14%; 14/97), muscularis propria (9%; 9/39), and seminal vesicle invasion (1%; 1/97). Clinical follow-up data was available for 80/89 (89%) patients with a mean duration of 35 months (range: 1-206 months). Metastatic UCa developed in 28/89 (35%) patients, 20/28 (71%) of which had invasive disease at presentation. Of the 17 (21%) patients who died, 12 (71%) initially presented with invasive UCa. Although more patients had non-invasive UCa, the propensity for worse outcomes in patients with invasive disease is greater compared to other urinary tract sites. These findings further emphasize the importance of early recognition of these tumors, in view of the relatively high preponderance of advanced disease and mortality in a subset of these patients.