Co-Occurrence of Hypophysitis and Thyroiditis Induced by PD-L1 Inhibitor Avelumab: Clinical Insights

Various endocrinopathies have been described in patients with malignancies who are receiving treatment with immune checkpoint inhibitors (ICIs). We present the case of a patient who was hospitalized with an acute alteration in mental status and was referred to the endocrinology service for evaluation of abnormal thyroid function tests. Subsequent investigation revealed the presence of acute adrenal insufficiency, which was successfully managed with steroid replacement therapy. This case highlights a unique simultaneous presentation of thyrotoxicosis due to thyroiditis and adrenal insufficiency due to hypophysitis in a patient treated with ICI avelumab for 5 months.