LBSAT308 A Tale Of Two Endocrinopathies: Hyperthyroidism And Hypophysitis In A Case of Metastatic Melanoma

Introduction: Several endocrinopathies have been associated with immunomodulator therapy, including hyperthyroidism, hypophysitis, and adrenal insufficiency. However, there have not yet been reports of more than one endocrinopathy in a single patient undergoing treatment with these agents. Clinical case: A 35 year old male was referred to Endocrinology after labs revealed hyperthyroidism. He had recently been diagnosed with melanoma that had metastasized to the liver and had been receiving dual immunotherapy with Nivolumab and Ipilimumab for 2 months. Routine labs from Oncology revealed TSH 0. 005 mIU/L (n 0.358-3.740 mIU/L), free T4 2.23 ng/dL (n 0.89-1.76 ng/dL), and total T3 232.3 ng/dL (n 60. 0-181. 0 ng/dL). Dual immunotherapy was discontinued given these findings. When he presented to Endocrinology, he endorsed nausea, vomiting, and chills. He was started on propranolol and a thyroid uptake scan was ordered. Two weeks later, the patient was unable to complete imaging due to fatigue, nausea, vomiting, and extremity pain. Labs at that time revealed PM cortisol 0.69 mcg/dL (n 3.44-16.76 mcg/dL), plasma ACTH <5 pg/mL (n 6-50 pg/mL), testosterone 74.5 ng/dL (n 123.1-813.9 ng/dL), prolactin 20.2 ng/mL (n 2.1-17.7 ng/mL), LH 9.80 mIU/mL (n 1.5-9.3 mIU/mL), and FSH 5.3 IU/L (n 1.4-18.1 IU/L). Interestingly, the patient's TSH and free T4 continued to reveal hyperthyroidism. A pituitary MRI demonstrated a 9 mm hypoechoic area at the posterior aspect of the pituitary. Given the lab and imaging findings, a diagnosis of hypophysitis was made. The patient was started on glucocorticoid therapy with good response. Over the next several months, a slow prednisone taper was initiated. Thyroid function returned to baseline normal values. He continued to be followed by Oncology for surveillance but has not been restarted on immunotherapy. Clinical lesson: Although there have been several reports of hyperthyroidism or hypophysitis in response to immunotherapy, this is the first reported case of a patient with dual endocrinopathies associated with immune modulator inhibition. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.