Fulminant Marginal Keratitis Induced by Atezolizumab, a Programmed Death Ligand 1 Inhibitor for Lung Cancer

INTRODUCTION: With the increasing use of immune checkpoint inhibitors, ocular adverse events have gained attention. We describe a case of atypical keratitis presumably induced by atezolizumab, a programmed cell death ligand 1 inhibitor. CASE PRESENTATION: A 73-year-old Japanese woman developed ring-shaped marginal infiltrations with epithelial breakdown of the corneas in both eyes. The patient had advanced small cell lung cancer and had received intravenous carboplatin, etoposide, and atezolizumab. She was treated with topical administration of 0.1% sodium phosphate betamethasone and 0.5% moxifloxacin six times daily. On day 14 following initial presentation, marked reduction of bilateral corneal infiltration was observed. During the succeeding cycles of chemotherapy, marginal keratitis did not recur, and then, the topical steroid was gradually tapered. CONCLUSIONS: Cancer immunotherapy, including atezolizumab, may lead to active T-cell recruitment into the cornea, which result in autoimmune corneal keratitis. We believe that this report is informative to both ophthalmologists and oncologists involved in the treatment of patients receiving cancer immunotherapy.