Over 90% of the UUTT are of urothelial origin (transitional cells) with almost 8% being squamous cell carcinoma The tumor growth pattern may be solid, papillary or mixed; the former presents a poor prognosis. Metastatic tumors can also affect the ureters.
Clinically, the most frequent sign is hematuria occurring in 75% - 90% of cases, followed by symptoms of obstruction mostly represented by flank pain (8% - 40% of cases), bladder irritation and constitutional symptoms. The image also shows advanced hydroureter and hydronephrosis with marked renal parenchymal atrophy. Some patients are asymptomatic, with diagnosis established after screening urinalysis demonstrates microhematuria or when abdominal ultrasonography is performed for an unrelated reason. Physical examination is routinely unrevealing. Cytologioc studies of the urine can be difficult to interpret because of degeneration of tumor cells in the urine but imaging studies generally demonstrate the tumor as well as the hydronephrosis.