Pembrolizumab induced life threatening adrenal crisis in a patient with recurrent adrenocortical carcinoma after unilateral adrenalectomy.

A 58-year-old female patient with recurrent left adrenal cortical carcinoma following surgery developed severe nausea, vomiting, anorexia, and hypovolemic shock, accompanied by profound hyponatremia, approximately 2 weeks after receiving pembrolizumab immunotherapy. She was diagnosed with an acute adrenal crisis. The patient had a prior history of mitotane therapy and radiotherapy. It was believed that the adrenal crisis was triggered by pembrolizumab-induced immune-mediated adrenalitis, compounded by cumulative damage to adrenal function from both the treatment and the tumor. After aggressive management, including anti-shock treatment, high-dose glucocorticoid replacement, and symptomatic supportive care, the patient's condition improved. At the 1-month follow-up after discharge, the patient had fully recovered, with normalized hormone levels and no evidence of tumor progression. This case highlights the potential for immune checkpoint inhibitor therapy to induce life-threatening adrenal crises in patients with pre-existing adrenal insufficiency. Clinicians must remain highly vigilant, performing early hormone level screening, promptly initiating hormone replacement therapy, and ensuring multidisciplinary team (MDT) collaboration to improve patient outcomes.