Renal cell carcinoma metastasis to the ciliary body responds to proton beam radiotherapy: a case report

INTRODUCTION: We report an unexpected presentation of metastatic renal cell carcinoma (RCC) to the ciliary body and an interesting response to proton beam radiotherapy. CASE PRESENTATION: We encountered a case of angle-closure glaucoma as the initial presentation of ocular metastasis to the ciliary body in a 65-year-old Caucasian man who had undergone right radical nephrectomy for RCC 15 years earlier. He underwent YAG (yttrium aluminium garnet) laser peripheral iridotomy while further metastatic workup took place. His condition was eventually diagnosed as stage IV metastatic RCC of the clear cell type and involved multiple sites, including the ciliary body, brain, lungs, liver, and pancreas. The progression of RCC metastasis to the ciliary body was studied for 16 months. The ciliary body mass continued to grow despite systemic treatment with temsirolimus and interleukin-2 and intravitreal injections of bevacizumab. The tumor size peaked at 6.11 × 6.06 mm before the start of proton therapy, which reduced the tumor size to 5.07 × 4.39 mm. CONCLUSIONS: RCC can produce metastases involving unusual sites many years after resection of the primary tumor. Proton therapy was found to be effective in treating RCC metastasis to the ciliary body in settings in which other treatment modalities failed.