2025 Proffered Presentations
S025: CLINICAL CHARACTERISTICS AND POSTOPERATIVE OUTCOMES IN A LARGE COHORT OF PATIENTS WITH DENSELY VERSUS SPARSELY GRANULATED SOMATOTROPH TUMORS
Kaasinath P Balagurunath, BA1; Christopher S Hong, MD1; Jakob V Gerstl, MBBS1; Ryan Chrenek, MD1; 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: As defined by the 2022 WHO Classification of Pituitary Tumors, densely granulated somatotroph tumors are characterized by immunopositivity for Growth Hormone (GH) as well as the alpha subunit, whereas sparsely granulated tumors do not stain positive for the alpha subunit. Despite their distinct classification and histology, there has been a lack of large-scale retrospective studies examining the outcomes, lesion characteristics, and prognostic significance of granulation pattern on postoperative outcomes.
Objectives: To characterize the clinical outcomes and postoperative outcomes in patients with symptomatic, operative acromegaly with densely versus sparsely granulated lesions.
Methods: In this single institution, retrospective study, a large cohort of 85 acromegaly patients who had GH and alpha subunit staining data available 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 granulation pattern was predictive of postoperative outcome.
Results: Among the 85 patients with staining data available from 2008-2024, 42 (49.4%) had densely granulated tumors and 43 (50.6%) had sparsely granulated tumors. The most common preoperative symptoms were headache (42.9% vs 32.6% in patients with densely vs sparsely granulated lesions), acromegalic-bone changes (73.8% vs 69.8%), and skin changes (33.3% vs 41.9% respectively). The rates of preoperative comorbidities and medication prescription were largely similar between groups.
Preoperatively, GH hypersecretion occurred in 92.9% of densely granulated lesions and 88.1% of sparsely granulated lesions. Hypothyroidism was another common endocrine abnormality, occurring in 11.9% and 21.4% of patients respectively. Postoperatively, hypercortisolism was the most common abnormality (82.5% vs 77.5%), alongside hypoprolactinemia (33.3% vs 39.5%). The rate of postoperative GH hypersecretion was higher in sparsely granulated lesions (39.5% vs 26.2% respectively).
All lesions included were intrasellar, with suprasellar-extension being more common in the sparsely granulated patients (47.5% vs 27%). The maximum diameter of lesions was largely similar (1.6 ± 0.9 cm vs 1.3 ± 0.7 cm in sparsely vs densely granulated lesions). The rates of intraoperative CSF leaks (46.5% vs 19%) and fat grafting (53.5% vs 28.6%) were higher in sparsely granulated tumors. Co-staining with FSH, LH, and prolactin occurred at higher rates in densely granulated lesions. In densely versus sparsely granulated lesions, the rates of biochemical remission (71.4% vs 80.6%) and recurrence (7.1% vs 14%) were largely similar.
Multivariate logistic regression demonstrated a dense granulation pattern was associated with a lower odds of developing any CSF leak (OR 0.32; 95% CI: 0.11, 0.91), but was not predictive of dysnatremia, recurrence, or biochemical remission when adjusted for covariates.
Conclusions: Overall, a dense granulation pattern was associated with a lower risk of developing a CSF leak.
