Abstract
INTRODUCTION: Renal cell carcinoma (RCC) metastasis to the paranasal sinuses is rare and lacks standard treatment, particularly for unresectable tumors. We report a case of sphenoid sinus metastasis with sarcomatoid differentiation successfully managed with radiation therapy and immunotherapy. CASE PRESENTATION: A 59-year-old male who had undergone left radical nephrectomy for RCC 13 years prior presented with acute left eye pain and tinnitus. Contrast-enhanced computed tomography (CT) revealed a hyper vascular sphenoid sinus mass with osseous destruction. Biopsy confirmed metastatic RCC with sarcomatoid differentiation. Given rapid symptom progression, intensity-modulated radiation therapy (39 Gy in 13 fractions) was initiated, followed by immunotherapy with nivolumab and ipilimumab. The patient developed complete blindness, which gradually improved during treatment. Serial CT showed a partial response sustained through four cycles. Subsequent 37 cycles of maintenance nivolumab showed persisting tumor reduction. CONCLUSION: Radiation with nivolumab and ipilimumab may be effective for unresectable paranasal sinus metastases of RCC.