Pembrolizumab-induced cytokine release syndrome with severe encephalopathy in the setting of clear cell vaginal carcinoma: A case report

•Pembrolizumab is increasingly used in the treatment of gynecologic cancers and has a half-life of 26 days.•Cytokine release syndrome with severe encephalopathy is a rare immune-mediated adverse effect.•Supportive care remains an important part of treatment of immune-mediated toxicity. It takes 5 half-lives to clear Pembrolizumab from the body.