2025 Proffered Presentations
S019: CLINICAL CHARACTERISTICS AND POSTOPERATIVE OUTCOMES IN A LARGE COHORT OF PATIENTS WITH ACTH COSTAINING SOMATOTROPH TUMORS
Ryan Chrenek, MD1; Kaasinath P Balagurunath, BA1; Christopher S Hong, MD1; Jakob V Gerstl, MBBS1; Sean Lyne, MD1; Noah L Nawabi, BS1; Rania A Mekary, PhD2; Timothy R Smith, MD, PhD1; 1Brigham and Women's Hospital; 2School of Pharmacy, Massachusetts College of Pharmacy and Health Sciences (MCPHS) University
Introduction: Growth hormone (GH) and adrenocorticotropic hormone (ACTH) secreting pituitary adenomas are believed to arise from distinct lineages and display different clinical characteristics and symptomatology. Acromegaly patients with tumors immunopositive for ACTH are a rare clinical entity that has been poorly described in the literature.
Objectives: To characterize the clinical characteristics and postoperative outcomes in acromegaly patients with ACTH positive lesions.
Methods: In this single institution, retrospective study, a large cohort of 156 acromegaly patients who had GH and ACTH staining data available between 2008-2024 were examined. All patients received transsphenoidal surgery with the aim of biochemical remission. Radiological, surgical, clinical, and endocrinological characteristics at baseline and postoperatively were tracked. Hormone values were determined at baseline and up to 3 years postoperatively. Pituitary adenoma size, location, and dimensions were determined using preoperative magnetic-resonance-imaging (MRI) and computerized-tomography (CT) imaging. T tests and chi-square tests were not performed due to the high type-1 error rate. A multivariate logistic regression model was created to determine whether ACTH staining was predictive of postoperative outcome.
Results: Among the 156 patients with staining data available, 38 (24.4%) demonstrated ACTH immunopositivity. The most common preoperative symptoms were headache (42.1% vs 40.7% in ACTH+ vs ACTH- patients respectively), acromegalic-bone changes (63.2% vs 78.8%), and skin changes (34.2% vs 35.6% respectively). Preoperative demographics, as well as the rates of comorbidities and preoperative medication prescription were largely similar between groups. Preoperatively, GH hypersecretion occurred in 75.7% of ACTH+ and 87% of ACTH- lesions. Hyperprolactinemia was another common endocrine abnormality, occurring in 27.3% and 21.7% of patients respectively. Postoperatively, hypercortisolism was the most common abnormality (56.8% vs 65.5%), alongside hypoprolactinemia (36.4% vs 31.4%). The rate of postoperative GH hypersecretion was higher in ACTH- lesions compared to ACTH+ tumors (32.2% vs 16.2% respectively).
ACTH+ somatotroph patients experienced lower rates of purely intrasellar lesions (80.6% vs 95.4%) and higher rates of macroadenomas (81.6% vs 67.8%). However, no other differences in lesion size, location, and macroscopic characteristics were observed. Lesions which were ACTH+ experienced higher rates of FSH (21.6% vs 2.6%), LH (23.7% vs 3.4%), TSH (21.1% cs 8.5%), and Prolactin (78.9% cs 55.1%) immunopositivity. All but two patients received endoscopic transsphenoidal surgery, and the most common Sellar reconstruction methods used were fat grafting and nasal packing. In ACTH+ vs ACTH- lesions, the rates of gross total resection (81.6% vs 84.7%), biochemical remission (73.3% vs 76.1%), and recurrence (7.1% vs 14%) were largely similar.
Multivariate logistic regression demonstrated that ACTH immunopositivity was not associated with an increased risk of developing surgical complications (dysnatremia or CSF leak), a failure to achieve biochemical remission, or recurrence when adjusted for covariates.
Conclusions: Overall, ACTH immunopositivity in acromegaly patients was not associated with worse postoperative outcomes despite differences in preoperative endocrine abnormalities and hormone co-staining.
