Pembrolizumab-Associated Stevens-Johnson Syndrome in a Patient With Metastatic Non-small Cell Lung Cancer: A Case Report

Pembrolizumab is a monoclonal antibody that binds to the programmed cell death-1 (PD-1) receptor and is approved for the treatment of several malignancies. We present a rare case of Stevens-Johnson syndrome (SJS) occurring in a 75-year-old female 14 days after receiving the first dose of pembrolizumab therapy to treat stage IV non-small cell carcinoma of the lungs with metastasis to the brain. Although pruritus and papular, erythematous rashes are documented after its use, severe reactions such as SJS and toxic epidermal necrolysis (TEN) are rarely seen in clinical practice. In addition to supportive care, the patient also received intravenous immunoglobulin (IVIG) and corticosteroid therapy and responded well to the therapy. Nearly complete re-epithelialization was achieved four weeks after the start of skin lesions. This case highlights a rare phenomenon of SJS- and TEN-associated adverse reactions following treatment with pembrolizumab.