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Tumors of the renal pelvis and ureter - Causes and pathogenesis
Last reviewed: 04.07.2025
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Cause of tumors of the renal pelvis and ureter
An increased risk of illness has been noted in individuals who have come into contact with petroleum products, plastics and plastics.
Chronic urinary infection, trauma, and stones may increase susceptibility to the development of transitional cell tumors and adenocarcinoma of the upper urinary tract.
Cyclophosphamide increases the risk of developing urothelial cancer. The reason for this is considered to be the negative effect of its metabolite - acrolein. As a rule, tumors caused by this effect have a high degree of differentiation. In addition, heredity can play a role in the development of cancer of the renal pelvis and ureter. There is a relationship between this type of tumor and Lynch syndrome II, which includes the early appearance of colon tumors and extraintestinal tumors.
Pathophysiology of tumors of the renal pelvis and ureter
Types of Upper Urinary Tract Tumors
The most common histological type of tumors of the upper urinary tract is transitional cell carcinoma, which is detected in 90% of patients. Its development is strictly correlated with smoking.
Squamous cell tumors account for 1-7% of urothelial tumors. Squamous cell carcinoma is often associated with the presence of secondary pyelonephritis against the background of nephrolithiasis. This histological variant of the tumor often has a moderate and low degree of differentiation. and is also characterized by early spread of the tumor process.
Adenocarcinoma accounts for less than 1% of neoplasms in this location. Often, patients with this histological variant of the tumor have stones that cause long-term obstruction of the upper urinary tract.
Inverted papilloma is an uncommon neoplasm of the upper urinary tract, which is considered benign. However, its malignancy is possible.
Growth and metastasis of tumors of the renal pelvis and ureter
Transitional cell tumors of the upper urinary tract spread strictly in the caudal direction. For example, a high frequency of relapses in the ureteral stump is noted in patients who have undergone nephrectomy, ureteral resection for renal pelvis cancer. On the contrary, relapses in areas located proximal to the ureteral lesion are practically not encountered. In 30-75% of patients with urothelial tumors of the upper urinary tract, bladder tumors develop during the course of the disease.
Transitional cell tumors of the renal pelvis and ureter are characterized by lymphogenous and hematogenous dissemination of the tumor process. Depending on the localization of the primary tumor, paraaortic, paracaval, common iliac and pelvic lymph nodes on the side of the neoplasm may be affected. Hematogenous metastases most often affect the lungs, liver and bones.
Frequency of transitional cell carcinoma of different parts of the upper urinary tract:
- renal pelvis - 58%;
- ureter - 35% (73% of tumors are localized in its distal part);
- renal pelvis and ureter - 7%;
- bilateral lesions - 2-5%.