# Successful Treatment of Paranasal Sinus Metastasis From Renal Cell Carcinoma With Immune Checkpoint Inhibitors and Radiotherapy: A Case Report

## TL;DR

A rare case of kidney cancer spreading to the sphenoid sinus was successfully treated with radiation and immunotherapy drugs.

## Contribution

This case report presents a successful treatment approach for a rare and challenging RCC metastasis using radiation and immune checkpoint inhibitors.

## Key findings

- The patient showed a partial response to radiation therapy followed by immunotherapy with nivolumab and ipilimumab.
- Blindness caused by the tumor improved during treatment, and tumor reduction was sustained over 37 cycles of maintenance therapy.

## Abstract

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.

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.

Radiation with nivolumab and ipilimumab may be effective for unresectable paranasal sinus metastases of RCC.

Although metastasis of renal cell carcinoma to the paranasal sinuses, particularly the sphenoid sinus, is exceedingly rare, no established standard of care exists for unresectable disease. Herein, we report a case of sphenoid sinus metastasis with sarcomatoid differentiation successfully managed with radiation therapy and a combination of immune checkpoint inhibition with nivolumab and ipilimumab.