2026 Proffered Presentations
S092: PSEUDOCAPSULE DISSECTION TECHNIQUE AND OUTCOMES IN GH-SECRETING PITNETS
Georgios A Maragkos, MD1; Jared Chung1; Gregory Hong, MD1; Michael Catalino, MD1; John Jane Jr., MD2; 1University of Virginia; 2Department of Neurosurgery, Carilion Clinic
Background: Pseudocapsular dissection is often associated with improved remission in corticotroph tumors, but its role in acromegaly is less certain. In growth hormone (GH) secreting pituitary neuroendocrine tumors (PitNETs), tumor size and invasiveness may dominate outcomes, potentially diminishing any independent effect of dissection technique.
Objective: To evaluate whether pseudocapsule dissection independently predicts remission in GH-secreting PitNETs after controlling for tumor size and invasiveness.
Methods: We retrospectively reviewed 88 consecutive patients who underwent endoscopic transsphenoidal surgery for acromegaly by a single senior surgeon between 2011–2024. Patients with prior surgery (n=9) or prophylactic radiation (n=2) were excluded. Intraoperative dissection was graded as: (1) one-piece, (2) near-total, (3) partial, or (4) piecemeal; for analysis, grades 1–2 were grouped as “Group A” and grades 3–4 as “Group B.” The primary outcome was biochemical remission per the 2023 Acromegaly Consensus Criteria, defined as age-adjusted IGF-1 normalization without adjuvant therapy. Secondary outcomes included surgery-only long-term remission and recurrence. Univariate and multivariable logistic regression analyses were performed, with adjustment for maximum tumor diameter and radiographic invasion (Knosp grade, sphenoid or cavernous sinus involvement).
Results: Of 88 patients (mean age 44±15 years, 49% female, 82% macroadenomas, 2 of which were giant adenomas >40mm diameter), intraoperative pseudocapsule was identified in 67%. Overall remission was achieved in 71/88 (80.7%) by 2023 criteria (100% for microadenomas, 79.4% for macroadenomas, 0% for giant adenomas). Surgery-only long-term remission was observed in 61/88 (69.3%) (100% for microadenomas, 64.7% for macroadenomas, 0% for giant adenomas). Group A dissection was achieved in 26 patients (30%), while Group B was performed in 62 patients (70%). Median [interquartile range IQR] follow-up was 40 months [22, 78] for the entire cohort, 52 months [14, 80] for Group A, and 37 months [19, 85] for Group B (p=0.98). Recurrence after remission occurred in 2/61 patients (3.3%) after a median of 50 months [22, 78]. Both patients were in Group B. On univariate analysis (Figure 1), Group A dissection was associated with higher rates of remission (96% vs 74%, p=0.017) and surgery-only long-term remission (92% vs 60%, p=0.002).
However, in multivariable models including tumor size and invasion, pseudocapsule dissection group was not independently associated with remission (OR 0.35, 95% CI 0.01–20.2, p=0.61), while maximum tumor diameter and invasion remained strong predictors. Visual analysis (violin plots, Figure 2) demonstrated that piecemeal resections were overrepresented among large tumors, and tumor size distribution explained most of the observed differences in outcomes between dissection groups.
Conclusions: In GH-secreting PitNETs, pseudocapsule dissection correlates with improved outcomes on univariate analysis, but this effect is explained by tumor size and invasiveness. Unlike corticotroph tumors, where pseudocapsule technique independently predicts biochemical remission, in acromegaly the surgical outcome is primarily driven by tumor invasiveness and size. These findings underscore the importance of achieving safe cytoreduction and low postoperative GH levels, rather than relying on pseudocapsule technique as a determinant of remission.