FRI347 Lymphocytic Hypophysitis In The Setting Of Necrotizing Granulomatous Inflammation

Disclosure: C. Kelly: None. L. Ghalib: None. Hypophysitis is rare; accounting for 0.24-0.39% of all pituitary diseases. Hypophysitis can be primary or secondary in nature. Granulomatous disease rarely causes pituitary enlargement, but Sarcoidosis and Granulomatosis with Polyangiitis have been documented to cause granulomatous infiltration of the pituitary. This case regards a man with granulomatous infiltration of the pituitary not consistent with either of the aforementioned disease processes. A 40 year old male presented to Urgent Care with headaches and blurry vision. Headaches were unresponsive to analgesics. The patient then presented to his PCP with the same complaints. MRI was then performed which showed a heterogeneously enhancing sellar and suprasellar mass. He was evaluated by Neurosurgery who recommended he undergo endoscopic resection of the pituitary lesion. Preoperative evaluation of pituitary axes were concerning for central hypothyroidism with a TSH of 1.046 uIU/mL (0.550-4.780) and free T4 of 0.76 ng/dL (0.89-1.76),as well as central hypogonadism with a FSH of 0.4 mIU/mL (<18.1), LH of 0.18 mIU/mL (1.5-9.3),and testosterone of 17 ng/dL (87-814). All other axes normal. Resection of the pituitary mass occurred approximately one week later at which time he was evaluated by Endocrinology for the first time. Prior to discharge, the patient was started on levothyroxine, but gonadal replacement was deferred to outpatient setting. Grossly the pituitary mass was concerning for lymphocytic hypophysitis (LH), and thus the patient was discharged on prednisone for empiric therapy. At the time of his endocrinology follow up, his headaches and visual changes had improved, but he was experiencing polydipsia, polyuria, and nocturia. Labs were consistent with Diabetes Insipidus (DI), and he was started on desmopressin. Surgical pathology had returned “acute and chronically inflamed granulation-like tissue associated with necrosis” confirming LH. CT chest was performed to evaluate for secondary causes of granulomatous disease which showed mediastinal lymphadenopathy without parenchymal lung disease. Serologic evaluation was positive for ANA, myeloperoxidase antibody, and SS-B antibody. While attempting to wean his prednisone the patient experienced recurrence of his headaches, which resolved when he returned to higher doses. The patient was evaluated by Pulmonology given the mediastinally mphadenopathy, who recommended bronchoscopy. When specimens from the mediastinal lymph nodes were evaluated by pathology, it was again significant for necrotizing granulomatous disease, but ACE and IL-2 were negative which argued against a diagnosis of sarcoidosis. He was evaluated by Rheumatology who recommended further infectious work upas well as consideration of initiation of a steroid-sparing agent for granulomatous disease. Workup of secondary etiologies for LH is ongoing given the systemic involvement. Presentation: Friday, June 16, 2023