[SMALL RENAL CELL CARCINOMA METASTASIS TO THE IPSILATERAL PERIRENAL FAT SYNCHRONOUSLY: A CASE REPORT]

Area of Science:

• Oncology
• Urology

Context:

• Small renal cell carcinoma (RCC) with metastases is uncommon.
• Synchronous metastasis to the ipsilateral perirenal fat in RCC is exceptionally rare, with this being the first reported case.
• The patient presented with early gastric carcinoma, incidentally found to have a right renal tumor and ipsilateral perirenal fat nodules.

Purpose:

• To report the first case of synchronous metastasis of small renal cell carcinoma to the ipsilateral perirenal fat.
• To describe the diagnostic and treatment course, including response to immunotherapy.
• To highlight the management of metastatic clear cell renal cell carcinoma.

Summary:

• A 70-year-old man with early gastric carcinoma was diagnosed with a 3 cm clear cell renal cell carcinoma (ccRCC) with synchronous metastasis to the ipsilateral perirenal fat (cT1aN0M1).
• Following laparoscopic radical nephrectomy, the patient developed multiple pleural metastases 11 months post-surgery.
• Treatment with pembrolizumab plus axitinib led to the disappearance of pleural metastases, although immunotherapy-related adverse events (diarrhea, hoarseness) necessitated treatment discontinuation. The patient remains recurrence-free at 36 months post-surgery.

Impact:

• This case expands the understanding of rare metastatic patterns in small renal cell carcinoma.
• It underscores the potential efficacy of combination immunotherapy (pembrolizumab plus axitinib) in managing metastatic ccRCC.
• The report highlights the importance of vigilant follow-up and management of immune-related adverse events in advanced RCC treatment.