Nivolumab-associated hypopituitarism in a 61-year-old woman with metastatic triple-negative breast.

Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape of cancer, enhancing response rates and survival outcomes. However, immune-related adverse events (irAEs), which can affect any organ or system, can limit their use. We report a rare case of hypophysitis in a triple-negative breast cancer patient receiving nivolumab, an anti-PD-1 monoclonal antibody. After six infusions of nivolumab, the patient developed hypocortisolism and hypothyroidism symptoms, such as mood swings, fatigue, unintentional weight loss, and vomiting. The diagnosis was confirmed by laboratory testing. The patient was successfully managed with hormone replacement therapy. Endocrinopathies can be life-threatening, necessitating treating doctors recognise their clinical symptoms, diagnose them, and manage them to ensure effective treatment and enhance the outcomes of immune checkpoint inhibitor-induced endocrine adverse effects.