Characteristic Pathological Features Of Keratinocyte Death In A Case Of Stevens-Johnson Syndrome Manifested By An Immune Checkpoint Inhibitor

A 71-year-old female was treated with pembrolizumab for lung cancer three months prior. However, pembrolizumab was discontinued, and prednisolone 50 mg/day and trimethoprim/sulfamethoxazole were started for immune checkpoint inhibitor (ICI)-induced interstitial pneumonia a month prior. She developed painful reddish erythema and blisters on palms and soles, sporadic erythema on trunk, and mucosal erosion when PSL was tapered to 27.5 mg/day (Fig. 1a-d). The skin biopsy showed keratinocyte death, which was dominant in basal layer, and remarkable interface change (Fig. 1e, f). Her symptoms improved with an increase in prednisolone to 50 mg/day.