THU084 Corticotroph Tumor Type Influences Clinical Presentation In Patients With Nonfunctioning Pituitary Neuroendocrine Tumors

Disclosure: N. Al-Shamkhi: None. B. Edén Engström: None. O. Gudjonsson: None. J. Wikström: None. O. Casar-Borota: None. E. Rask: None. Introduction: According to the current World Health Organization classification of endocrine tumors the classification of non-functioning pituitary neuroendocrine tumors (NF-PitNET) is based on pituitary cell lineages, defined by immunohistochemical expression of anterior pituitary hormones and pituitary specific transcription factors. The second most common NF-PitNET type, after silent gonadotroph tumors, are silent corticotroph tumors that are regarded as a potentially more aggressive type. If there is indication for treatment, the first-line treatment is transsphenoidal surgery. Some, but not all studies have shown a higher degree of preoperative pituitary failure or more frequent postoperative pituitary failure in patients with silent corticotroph tumors compared to the other NF-PitNET. Objectives: We compared patients with silent corticotroph and silent gonadotroph tumors, and explored whether tumor type and radiological findings were associated with pre- or postoperative pituitary failure. Design and method: One hundred patients who underwent surgery for NF-PitNET at the same tertiary center were included. Data regarding age at surgery, sex, pre- and postoperative pituitary function and tumor type, were collected after chart review. Preoperative MRI examinations were revised regarding tumor volume and Knosp classification. Results: The majority, 72% (72/100) were classified as silent gonadotroph tumors followed by 18% (18/100) silent corticotroph tumors. Patients with silent corticotroph tumors were younger at surgery, P=0.003. There were no differences regarding sex, preoperative tumor volume, invasive growth on MRI, defined as Knosp grade > 3, pituitary failure or prolactin elevation between the two tumor types. Binary logistic regression showed that having a silent corticotroph tumor, P=0.04, odds ratio 5.7 (CI: 1.06-30.71), higher age at surgery, P=0.003, odds ratio 1.07 (CI: 1.02-1.13), and a larger preoperative tumor volume, P=0.01, odds ratio 1.18 (CI: 1.04-1.33), were all factors associated with an increased likelihood of having postoperative pituitary failure. Sex, invasive growth and preoperative prolactin elevation were not significant predictors of postoperative pituitary failure in the binary logistic regression. Conclusion: The results indicate that silent corticotroph tumors influence the clinical presentation of NF-PitNET. Patients with silent corticotroph tumors were significantly younger at surgery, and demonstrated an increased likelihood of postoperative pituitary failure. Presentation: Thursday, June 15, 2023