1.Pathology Most of the renal collecting system tumors (more than 90%) are uroepithelial metastatic cell carcinoma, and the differentiation and basal infiltration degree of tumor cells can vary greatly. Tumors can be solitary or multiple. Because of the thin muscle layer of pelvic calyx wall and abundant surrounding lymphatic tissue, there are often early lymphatic metastases. Squamous cell carcinoma is rare and is mostly related to long-term stimulation of urinary stones and infection. 2. Clinical manifestations and diagnosis The average age of onset is 55 years old, and most of them are between 40 and 70 years old. The ratio of male to female is about 2:1. Early manifestation is intermittent painless meatus hematuria throughout the whole process, often without swelling or pain, and occasionally renal colic due to blockage of ureter by blood clots. Physical signs are not obvious. Urine cytology is relevant for the diagnosis of high-grade tumors. Intravenous urography and retrograde pyelogram show filling defects or deformation in the renal pelvis, but should be differentiated from uric acid stones or blood clots. ultrasound or CT examination can exclude stones, and CT can also be used for local staging of the tumor. Cystoscopy can see bloody urine ejected from the ureteral orifice, and ureterorenoscopy is also of great value for diagnosis. Migratory cell carcinoma has a tendency to occur multicentrically in the urinary tract, with a 1-2% incidence in the contralateral kidney and up to 40-50% in the ureter and bladder. It is important to examine these potential sites of development, and intravenous urographic films should be carefully reviewed and cystoscopy should be carefully performed. 3. Treatment Surgical removal of the kidney (including perinephric fat and perinephric fascia), full-length ureter and bladder wall at the ureteral opening. Local resection or endoscopic surgery is also feasible for well-differentiated tumors without infiltration after biopsy, but mostly for patients with isolated kidney, bilateral tumors or renal insufficiency. 4.Prognosis Most of the metastatic cell carcinomas are low-grade, non-invasive tumors. The 5-year tumor-free survival rate after total resection of the upper urinary tract on the affected side is higher than 90%, while the survival rate of patients with invasive renal parenchyma or high-grade tumors is lower. The possibility of tumor development in the remaining uroepithelial organs should be noted during follow-up.