Adrenal Insufficiency Induced by Checkpoint Inhibitor Therapy in a Patient With Metastatic Acral Melanoma: A Case Report

Immune checkpoint inhibitors (ICIs) have transformed the therapeutic landscape of advanced melanoma; however, their clinical benefit is tempered by a widening spectrum of immune-related adverse events (irAEs), including endocrine dysfunction. Among these, hypophysitis and adrenal insufficiency remain under-recognised, yet potentially life-threatening complications. We describe a case of secondary adrenal insufficiency in a 78-year-old female with unresectable Stage IIIC acral melanoma treated with nivolumab and relatlimab. She presented with profound hyponatraemia, hypotension, and fatigue. Subsequent evaluation confirmed central adrenal insufficiency. Glucocorticoid replacement led to rapid clinical improvement. This case underscores the imperative for heightened clinical vigilance in patients receiving ICI therapy. Recognition and prompt intervention are crucial to reducing morbidity and optimising oncologic and endocrine outcomes, which could range from thyroid dysfunction and adrenal insufficiency to hypophysitis, as the case underscores the clinical complexity of diagnosing ICI-related endocrinopathies and highlights the need for high clinical vigilance and structured endocrine surveillance in patients undergoing immune checkpoint blockade.