Unclassified renal cell carcinoma with multi-organ metastasis treated with surgery and targeted therapy combination: a case report and literature review.

We present a rare case of unclassified renal cell carcinoma (RCC) in a 66-year-old woman, exhibiting multi-organ invasion. The patient was asymptomatic until a health exam revealed a left renal mass. CT scans showed an irregular, 6.8 × 8.9 cm mass involving the renal sinus, with possible pancreatic infiltration and retroperitoneal lymph node metastasis. Intraoperative findings necessitated multi-organ resection, including the left kidney, spleen, and portions of the pancreas. Histopathology confirmed unclassified RCC, positive for CA-9, CD10, Vim, and negative for P504S, CD99, Desmin. Post-surgery, the patient received cabozantinib and nivolumab, and remains progression-free at 22 months of follow-up. This case analyzed the diagnosis and treatment of aggressive unclassified RCC, and showed good efficacy after extensive surgical resection and combined treatment with cabozantinib and nivolumab, which may help further study of unclassified RCC.