Differential diagnosis of upper urinary tract tumors

Imaging and evaluation of upper urinary tract structures

The radiological presentation of upper urinary tract pathologies requires careful differential diagnosis, as the same symptoms carry different weight depending on the level of the lesion. Overall, urothelial thickening is associated with malignant growth in slightly less than half of all clinical cases. However, this statistic changes when broken down by anatomical segment.

In the proximal segments of the renal collecting system (calyces and renal pelvis):

• Urothelial thickening is an extremely alarming sign and almost always indicates the development of a neoplastic process.
• Filling defects detected on contrast-enhanced imaging turn out to be true neoplasms in only 50% of cases.

In the ureters, the opposite trend is observed:

• Urothelial thickening is of malignant nature in only a third of cases.
• Filling defects, conversely, represent tumor masses with a high degree of probability.

Non-muscle-invasive cancer and superficial tumors

All urothelial neoplasms, regardless of their grade, require mandatory treatment. This rule applies even to papillomas and papillary tumors of low malignant potential (PUNLMP). The need for an active approach is driven by the fact that low-grade lesions (low-grade) can cause pronounced clinical symptoms, primarily hematuria. In addition, accurate pathomorphological verification of tissues is critically important for establishing the final diagnosis.

The primary treatment method is transurethral resection (TUR). It is often supplemented by adjuvant local therapy, such as intravesical BCG instillation or other agents. The initial response to such therapy is rated as excellent in 70–80% of patients. Nevertheless, 70% of patients experience recurrences—new bladder tumors—within a few years. Although only a minority of recurrences progress to a muscle-invasive form, all patients require strict and regular monitoring.

Management of localized muscle-invasive cancer

According to the European Association of Urology (EAU) guidelines, the drug of choice and gold standard for patients with localized non-metastatic muscle-invasive disease is radical cystectomy (RC). To achieve optimal oncological outcomes, the surgical intervention must be performed strictly within 3 months of diagnosis.

A mandatory routine step of the operation is lymph node dissection. Although its ideal extent is still debated, it has been proven that extended dissection yields better results compared to standard dissection. The EAU also insists on using nerve-sparing techniques to preserve sexual function in patients of both sexes, as this does not compromise oncological outcomes.

Following bladder removal, urinary diversion is required. There are three main approaches:

1. Urinary diversion to the anterior abdominal wall (e.g., ileal conduit).
2. Formation of an artificial reservoir—an orthotopic neobladder.
3. Rectosigmoid diversion.

The first two methods are the most widely used. If there are no strict contraindications, patients (both men and women) are recommended to undergo orthotopic substitution or ileal conduit formation.

Advanced disease and lymph node involvement

By the time treatment begins, the tumor has already spread beyond the organ in some patients, and isolated surgery loses its radical potential. Statistics show that approximately 25% of patients are found to have regional lymph node metastases during cystectomy.

Metastasis radically alters the prognosis of the disease:

• With an N0 lymph node status (no involvement), the 5-year survival rate ranges from 40% to 80%.
• In the presence of metastases (stages N1, N2, or N3), this figure drops precipitously to 20–25%.

PET-CT is actively used to detect the extent of the disease. Malignant foci demonstrate increased uptake of fluorodeoxyglucose (FDG). Typical localizations, in addition to the pelvic organs, include para-aortic nodes in the abdominal cavity and left supraclavicular lymph nodes. With confirmed lymph node involvement, patients require mandatory systemic chemotherapy or radiation therapy, which can be administered in neoadjuvant, adjuvant regimens, or as an alternative to bladder removal.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Pathomorphological classification of urothelial tumors and PUNLMP criteria.
• Mechanisms of action of BCG therapy and other intravesical agents following TURBT.
• Comparative analysis of extended versus standard lymph node dissection in cystectomy.
• Surgical technique for orthotopic neobladder construction and ileal conduit formation.
• Indications for neoadjuvant chemotherapy upon detection of metastasis on PET-CT.

Other topics in the section "Diagnostic Radiology of the Abdominal Organs"

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