MON-LB075 Etiological Spectrum and Change Pattern of Pituitary Stalk Thickness: A Single Center Experience in 321 Patients

Objective: With difficulty in biopsy of pituitary stalk, the etiologic diagnosis of pituitary stalk thickness (PST) remains a big challenge. This study was to summarize etiologies of PST and the natural course of indistinguishable PST. Methods: Patients with magnetic resonance imaging (MRI) confirmed PST in our hospital from January 2014 to May 2017 were reviewed. Clinical information including onset symptoms, laboratory, imaging, operative and pathological data and follow-up were collected. Results: Of 321 eligible PST patients, 28.3% were pediatric under 18 years. Central diabetes insipidus was the initial symptom in 68.8% patients. 57.6% patients had at least one anterior pituitary hormone deficit. Adjusted OR of panhypopituitarism associated with hypothalamus involvement was 7.3 (95%CI 3.0-17.8, p<0.001). Confirmed diagnoses were established in 137 (42.7%) patients, including neoplasms(n=103, 75.2%), inflammation(n=18, 13.1%) and congenital anomalies(n=16, 11.7%). Intracranial germ cell tumor(66.7%) was the leading cause among pediatric patients, while histiocytoses(20.0%) and malignant metastases(14.7%) were the most common reasons in adults. Of 38 indistinguishable PST patients, they had second MRI at median time 4.4 months(0.8~9.7). After median time 8.5months (0.8~35.2), spontaneous remission was observed in 17 patients(44.7%), with complete remission in 14 (36.8%) and partial remission in 3 (7.0%), respectively; five(13.2%) patients had progression, and the remaining 16 (42.1%) stabilized. By cox regression analysis, patients with first follow-up interval shorter than 4.5 months were 6.4-fold (95% CI 1.4-29.3, p=0.017) more likely to have spontaneous remission than those delayed the first follow-up. Conclusion: PST is highly heterogeneous, most confirmed cases attributed to neoplasm. Etiology spectrum varies greatly with age. Physicians must be familiar with the major differential diagnoses, necessary investigations and follow-up. Biopsy is indicated when radiological progression and/or pituitary function worsening is detected. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.