Retinal Vasculitis Associated with Tislelizumab in a Patient with Esophageal Squamous Cell Carcinoma

Purpose: To describe a case of retinal vasculitis associated with tislelizumab, an anti-PD-1 monoclonal antibody, in a patient with esophageal squamous cell carcinoma (ESCC). Methods: Case report. Results: A 60-year-old man undergoing treatment with tislelizumab for ESCC was referred for ophthalmologic evaluation. The patient was asymptomatic, but fundoscopic examination revealed peripheral intraretinal hemorrhages in the right eye. Fluorescein angiography revealed bilateral retinal vasculitis that was successfully controlled with systemic corticosteroids without discontinuation of tislelizumab. Four months after prednisone cessation, the patient relapsed with bilateral vision loss, and optical coherence tomography demonstrated subfoveal fluid in both eyes. Oral prednisone was reintroduced, leading to resolution of the subfoveal fluid, though visual acuity did not fully recover. Conclusions: To our knowledge, retinal vasculitis associated with tislelizumab has not been previously reported. This case highlights the need for close ophthalmologic monitoring in patients receiving immune checkpoint inhibitors, as ocular immune-related adverse events can develop or recur at any point during treatment and even be asymptomatic.