FRI328 Granulomatous Hypophysitis With Magnificent Response To Glucocorticoids

Disclosure: M. Rodriguez Caballero: None. F. Romero: None. C. Escurra: None. R. Rodriguez: None. R. Rolon: None. E. Valinotti: None. A. Ayala: None. Granulomatous hypophysitis corresponds to 1% of sellar lesions. It maybe primary or secondary to tuberculosis, Pneumocystis carinii, Toxoplasma gondii, Cytomegalovirus or parasitic infections. Non-infectious etiologies include sarcoidosis, vasculitis, dendritic cell disorders, ruptured Rathke cysts or Crohn's disease. A 59-year-old immunocompetent woman was evaluated for decreased visual acuity, diplopia, and palsy of the 6(th) cranial nerve. Asellar MRI confirmed an 18 x 14 x 12 mm pituitary lesion with chiasmatic compression and visual field involvement. Hormonal evaluation revealed a TSH 0.03 mIU/L, FT4 0.44 ng/dL, random of GH 5.64 ng/mL, FSH 55.2 IU/mL, LH33.1 mIU/mL, and cortisol of 16 ng/dl. There was no evidence of diabetes insipidus. Transsphenoidal resection resulted in visual field improvement with a noticeable residual tumor of 12 x 9 x5 mm within the sellar space on the postoperative MRI. The patient developed panhypopituitarism. Pathology revealed non-caseous granulomatosis, with histiocytic aggregates of giant cells forming granulomas, with negative immunohistochemistry for mycobacteria. Tuberculin test, VDRL, blood cultures, ANA, Anti-DNA, ANCA C and P were negative. Tomography images and PET scan ruled out systemic involvement. The patient was treated with high doses of glucocorticoids under a presumptive diagnosis of isolated pituitary sarcoidosis vs. primary hypophysitis, resulting in complete disappearance of the lesion. Conclusion: Granulomatous hypophysitis is the second most common cause of chronic inflammation of the pituitary gland mimicking pituitary adenomas. Surgical removal and glucocorticoids are often utilized although there is no consensus regarding the treatment. Our case illustrates the importance of considering this diagnosis when confronted with incidental sellar lesions. Pharmacotherapy resulted in symptomatic improvement and complete involution of the pituitary lesion confirming the utility of empiric high-dose glucocorticoid as a therapeutic strategy for granulomatous hypophysitis. Presentation: Friday, June 16, 2023