A case of hypertensive retinopathy developing during pembrolizumab treatment for intrahepatic cholangiocarcinoma

To report the first documented case of severe vision loss due to secondary hypertensive retinopathy associated with pembrolizumab therapy, thereby expanding the known spectrum of ocular toxicities from immune checkpoint inhibitors (ICIs). A 54-year-old woman with intrahepatic cholangiocarcinoma developed acute bilateral vision loss during a treatment cycle of pembrolizumab combined with gemcitabine and oxaliplatin. Her best-corrected visual acuity (BCVA) at presentation was 0.15 (approximately 20/133) in the right eye and 0.12 (approximately 20/167) in the left, with new-onset severely elevated blood pressure (168/117 mmHg). Dilated fundus examination revealed classic signs of hypertensive retinopathy, including arteriolar attenuation, hemorrhages, cotton-wool spots, and macular edema. Fluorescein angiography revealed an absence of the vascular wall staining and leakage typical of immune-mediated retinovasculitis. Following a diagnosis of secondary hypertensive retinopathy, she was started on oral antihypertensive agents (sacubitril/valsartan). Her vision and macular anatomy showed marked improvement with prompt antihypertensive therapy and intravitreal anti-VEGF injections. At the final follow-up, her BCVA had improved to 0.8 (approximately 20/25) in the right eye and 0.5 (approximately 20/40) in the left. This case suggests that pembrolizumab may be associated with severe hypertension manifesting as vision-threatening retinopathy, which appears clinically distinct from primary ocular immune-related adverse events. Consequently, hypertensive retinopathy should be considered in the differential diagnosis of acute vision loss during ICI therapy. Furthermore, routine blood pressure monitoring is recommended to prevent misdiagnosis and to preserve the continuity of both vision and anticancer treatment.