Sudden Vision Loss in a Patient With Renal Cell Carcinoma: A Potential Indicator of Choroidal Metastasis.

Choroidal metastasis of renal cell cancer (RCC) is an exceptionally rare clinical occurrence. In most cases, sudden vision loss is the first symptom. Here we present the case of a 52-year-old male with papillary RCC first diagnosed in 2018. Three years later, a bronchoscopy with endobronchial ultrasound (EBUS) identified suspicious infracarinal lymph nodes. A biopsy confirmed metastasis from RCC, leading to the initiation of systemic first-line therapy with cabozantinib monotherapy. The patient confirmed an excellent response with complete remission. In 2023, the patient reported for the first time a bilateral decrease in vision. Initial management with corrective lenses was unsuccessful. Further staging indicated metastases in the liver, spleen, and adrenal gland. Consecutively, the therapy was switched to lenvatinib and pembrolizumab. Two months later, an ophthalmologic examination due to persisting vision loss confirmed bilateral choroidal metastases. The systemic therapy was continued, and the patient's vision significantly improved. In 2024, the patient developed immune-associated pneumonitis, initially treated with prednisolone. The pulmonary situation became worse. A CT scan confirmed additional metastases in the lung with lymphangiosis carcinomatosis. Due to a poor performance status, no further systemic therapy has been initiated to date. In conclusion, this case highlights the rarity of choroidal metastases in RCC and the challenges of diagnosis. Ophthalmologic examination in RCC patients experiencing sudden vision loss is essential to detect these specific metastases as soon as possible. Comprehensive documentation and awareness of these rare metastatic manifestations are essential to improving diagnostic accuracy and patient outcomes.