# Clear Cell Renal Cell Carcinoma with Synchronous Bladder Metastasis: Diagnostic, Surgical, and Pathological Insights from a Rare Presentation

## TL;DR

This case study describes a rare instance of kidney cancer spreading to the bladder at the same time, highlighting the importance of thorough diagnosis and combined treatment approaches.

## Contribution

The paper presents a rare case of synchronous bladder metastasis in clear cell renal cell carcinoma and emphasizes the value of multidisciplinary treatment strategies.

## Key findings

- Robot-assisted surgery enabled precise removal of the primary tumor and metastases with minimal complications.
- Combined immune checkpoint inhibitor and tyrosine kinase inhibitor therapy was initiated to target residual metastases.
- Histopathology and immunohistochemistry confirmed the diagnosis of ccRCC with bladder metastasis.

## Abstract

Background: Clear cell renal cell carcinoma (ccRCC) constitutes 75–80% of all renal cell carcinomas and exhibits aggressive behavior with high metastatic potential. Common metastatic sites include lungs, bones, lymph nodes, and liver, while urinary bladder involvement is exceedingly rare. Early detection of atypical metastases is critical for risk stratification, surgical planning, and systemic therapy selection. Methods: We report a 69-year-old male presenting with recurrent, painless gross hematuria and dysuria. Contrast-enhanced computed tomography revealed a left renal mass with bilateral pulmonary nodules, regional lymphadenopathy, and a bladder lesion. The patient underwent transurethral resection (TUR) of the bladder lesion, followed by robot-assisted left nephro-adrenalectomy with para-aortic lymphadenectomy. Histopathology and immunohistochemistry (PAX8+, CD10+, CAIX+, CK7−, GATA3−) confirmed ccRCC with synchronous bladder metastasis. Postoperatively, combined immune checkpoint inhibitor (ICI) therapy and tyrosine kinase inhibitors (TKIs) were initiated. Results: TUR provided symptomatic relief and diagnostic confirmation. Robot-assisted surgery enabled precise, oncologically safe excision of the primary tumor and regional metastases with minimal blood loss and no perioperative complications. Pathological staging was pT3aN1M1, ISUP grade 2, with lymphovascular invasion, confirming advanced disease requiring systemic therapy. Early initiation of ICI plus TKI therapy targeted residual micrometastases to potentially prolong survival. Conclusions: This case highlights the rare occurrence of ccRCC with synchronous bladder metastasis and underscores the importance of comprehensive imaging, detailed morphologic and immunohistochemical evaluation, and a multidisciplinary approach. Robot-assisted cytoreductive surgery combined with modern systemic therapy represents an effective strategy for advanced ccRCC, emphasizing the need for individualized treatment and long-term follow-up in atypical metastatic scenarios.