1.What are the general ways to detect and diagnose renal pelvis cancer? The possibility of renal pelvis cancer should be considered for any patient with hematuria of the naked eye. Commonly used examination methods include: (1) Laboratory examination: routine urine examination can often detect red blood cells. Urine exfoliative cytology examination needs to be performed several times, and the positive rate is about 35% to 55%. Urine cells for liquid-based thin-layer or DNA ploidy analysis is also a new diagnostic method that has emerged in recent years. （Ultrasound is a simple, non-invasive test. The direct signs and characteristics of ultrasound examination are: solid mass echogenicity in the renal pelvis, irregular mass margins, and mass echogenicity below the renal parenchyma. Indirect signs are: a limited dilatation of the collecting system of the renal pelvis with irregular echogenicity when the tumor is small. When the tumor is larger, the echogenicity of the collecting system is interrupted and the dilatation is obvious, and fluid accumulation in the renal pelvis and calyces occurs, characterized by mild fluid accumulation in the renal pelvis and dilatation in some of the calyces. Upper urinary tract tumors often cause different degrees of urinary tract obstruction. Ultrasound is extremely sensitive to diagnose urinary tract hydrocele and accurate localization of the lesion. High-resolution color ultrasonography can observe the distribution of blood flow within the tumor. This has some significance in the differential diagnosis of tumor and blood clot. (3) Intravenous pyelogram is an important measure for the diagnosis of upper urinary tract disease. In this disease, papillary tumors mainly present as eccentric filling defects or cupping obstruction. However, if the tumor causes complete obstruction or serious impairment of renal function, the affected kidney is often not visualized, which can seriously affect the localization and qualitative diagnosis of this disease. In this case, retrograde urography of the upper urinary tract should be performed routinely in cases where intravenous pyelogram shows no visualization of the upper urinary tract on one side. Retrograde pyelogram can achieve local diagnosis and qualitative diagnosis by cytological examination. (4) CT and MRI scans have the advantages that other imaging examinations cannot match in the diagnosis and preoperative staging of this disease, and CT and MRI examinations have high density resolution and can clearly show the lesion density, infiltration range and relationship with surrounding organs after scanning plus enhancement scan. The blood supply of renal pelvis cancer is less than that of renal cancer, and after contrast injection, only mild to moderate enhancement is achieved, and the CT value is less enhanced. When renal pelvis tumor invades renal parenchyma, the density of tumor in enhanced scan is significantly lower than that of renal parenchyma. CT and MRI scans can not only directly and clearly show the tumor itself, but also distinguish renal pelvis cancer from renal cell carcinoma invading renal pelvis, and clearly observe perinephric infiltration and regional lymph node metastasis. It helps the surgeon to decide on the surgical incision, scope and preoperative staging. (5) All patients with renal pelvis cancer should undergo cystoscopy before surgery to exclude the possibility of bladder tumor. Urine exfoliative cytology examination is important for the qualitative diagnosis of renal pelvic cancer. With the progress of luminal urology technology, ureteroscopy plays an important role in the diagnosis of renal pelvis cancer. Ureteroscopy can be performed for any suspected renal pelvis tumor that cannot be confirmed by IVU, CT and ultrasound. 2.What is the difference between renal pelvic cancer and renal cancer? How to differentiate them? (1) Renal pelvic cancer originates from the uroepithelium and grows mainly in the renal pelvis. (2) Kidney pelvic cancer has hematuria in the early stage, while kidney cancer has hematuria in the late stage when the tumor invades the renal pelvis; (3) Kidney cancer shows multivessel lesions on enhanced CT, and its enhancement is more than that of renal pelvic cancer. Patients with renal pelvis cancer are more likely to show peripelvic lymph node changes on CT. (4) Urine exfoliative cytology may be positive in renal pelvic carcinoma, while most urine exfoliative cytology is negative in renal carcinoma.