Pembrolizumab-induced myasthenia gravis: Two patients' experiences.

Checkpoint inhibitors are increasingly used to treat patients with gynecologic malignancies and can cause rare and unusual side effects, also known as immunotoxicities, that are rarely observed in patients receiving traditional immunotherapy. If these are not identified and treated, they can cause disability and even death for patients undergoing treatment. This report describes the range of pembrolizumab-induced myasthenia gravis (MG) immunotoxicity through two cases. The first patient is an 85-year-old woman with recurrent vulvar carcinoma who completed two cycles of pembrolizumab. She had a severe presentation leading to respiratory failure. The second patient is an 80-year-old woman with recurrent serous endometrial carcinoma who developed isolated ocular myasthenia after her second cycle of pembrolizumab. The symptoms and physical examination findings described here illustrate the breadth of symptom severity associated with pembrolizumab-induced MG and importance of early identification and treatment to minimize symptoms and improve outcomes.