Pembrolizumab-induced thyroid storm

Immune checkpoint inhibitors (ICIs) are novel treatment modalities that have revolutionized the field of oncology. Their widespread use in various cancers and prolonged survival of patients led to the identification of a wide range of side effects associated with the therapy, known as immune-related adverse effects (irAEs). IrAEs are presumed to arise from immunologic enhancement and frequently result in endocrine disorders. Thyroid dysfunction is not uncommon during therapy with pembrolizumab and affects up to 13% to 14% of patients. Thyroid storm associated with ICIs is extremely rare. We present a case of a 34-year-old woman with metastatic ovarian carcinoma who developed thyroid storm shortly after an addition of pembrolizumab.