SUN-304 Hypophisitis in Patients with and Without Autoimmune Rheumatological Disease

Background: Hypophysitis is an inflammatory process of the pituitary gland with different origins. Infundibulum may be also involved, called infundibulum-hypophysitis. Sometimes, enlargement of pituitary gland causes mass effect and anterior or posterior hormonal dysfunction, including hypopituitarism, and diabetes insipidus (DI), respectively. Hypophysitis is a rare autoimmune disease, however, the number of cases have been recently increasing due to higher detection related with more magnetic resonance imaging (MRI) studies. In addition, hypophysitis may be related with autoimmune rheumatologic disease (ARD) such as generalized lupus erythematosus (GLE), granulomatosis with polyangeitis (GPA), IgG4-related disease, and rheumatoid arthritis (RA). Aim: to compare the clinical and biochemical findings among patients with hypophysitis grouped depending on the presence of coexistent ARD activity. Methodology: it is a comparative and cross-sectional study. We registered all data from cases followed-up in Neuroendocrinology and Rheumatology units, from January 1987 to July 2019. Results: 24 patients showed confirmed diagnosis of hypophysitis. Majority of them (n=17, 71%) do not have coexistent diagnosis of ARD. However, 7 cases (29%) presented pituitary involvement with coexistent activity of GPA (n=4, 17%), GLE (n=1, 4%), RA (n=1, 4%) and IgG4-related disease (n=1, 4%). Female gender predominate in hypophysitis cases with and without ARD (p=0.9). Interestingly, age of hypophysitis diagnosis was significantly younger in cases without (38±14) vs. with (49±5) ARD (p=0.01). MRI results showed similar and typical findings related with hypophysitis independently of the presence of ARD. Hypopituitarism was present in the majority of cases, however, none of cases with hypophysitis and ARD showed hypogonadism (p=0.02). DI was present in 15 patients (63%), three of them with ARD (all with GPA). All cases received only medical therapy (i.e., glucocorticoids, rituximab, or azathioprine). Surgery or radiotherapy was not necessary in any case. Conclusions: Almost a 30% of cases with hypophysitis may have coexistent ARD. Pituitary function should be evaluated in cases with previous ARD diagnosis. However, hypogonadism was not present in cases with ARD and hypophysitis. Patients with ARD presented hypophysitis at older age. The remaining clinical and radiological data were similar between groups. References: 1) Clinical Diabetes and Endocrinology. December 2016;2(1). 2) Clin Rheumatol. 2019 Aug 24. doi: 10.1007/s10067-019-04735-7