What happened, in summary

A 63-year-old man with non-small cell lung cancer had a right adrenal metastasis at diagnosis, supporting Stage IV disease. He was treated with pembrolizumab. Over the next 18 months, he developed several immune-related complications, including destructive thyroiditis, interstitial pneumonitis, and eosinophilic enteritis. Pembrolizumab was ultimately stopped 537 days after the first dose. Long-term steroid treatment for pneumonitis complicated the picture further, and he later developed fatigue and other symptoms linked to adrenal insufficiency and impaired pituitary ACTH secretion. Hydrocortisone replacement improved his symptoms. Importantly, later PET/CT showed no abnormal uptake in either the primary lung lesion or the known right adrenal metastasis. The cancer therefore remained well controlled despite the need to stop immunotherapy because of toxicity. He continued endocrine replacement treatment after discharge.