2025 Poster Presentations
P211: A COMPARATIVE ANALYSIS OF GROWTH HORMONE-SECRETING MIXED GANGLIOCYTOMA-PITUITARY ADENOMAS AND PURE GROWTH HORMONE PITUITARY ADENOMAS
Hailey Mattheisen, MS; Abigail K Peterson, BS; Abdullah Memon, BS; Margaret Allen, BS; E. Kelly S Mrachek, MD, MS; Samon Tavakoli, MD; Nathan Zwagerman, MD; Stephanie Cheok, MD; Medical College of Wisconsin
Introduction: GHPA and MGPA Comparison of Patient Demographics and Clinical Courses Mixed gangliocytoma-pituitary (PitNET) adenomas (MGPAs) are rare composite tumors that comprise less than 0.5% of sellar masses, per the 2022 WHO Classification of Endocrine and Neuroendocrine Tumors, 5th ed. The most common pituitary adenoma component is a somatotroph tumor (approximately 50%), most commonly as a sparsely granulated somatotroph tumor with characteristic fibrous bodies, and these patients often present with signs and symptoms of acromegaly. The pathogenesis of this tumor is still being investigated as few cases have been reported in literature. We present our institutional experience in the surgical management of GH-secreting MGPAs and compare this subgroup with patients with growth hormone-secreting adenomas (GHPA).
Methods: We collated and retrospectively reviewed demographic and clinical data of adult patients with MGPAs and GHPAs operated at our institution from 2018 to 2024.
Results: Results are summarized in Table 1. Our inclusion criteria yielded 5 patients with MGPA (3 males, 2 females) and 41 patients with GHPA (20 males, 21 females). The mean age of the MGPA group was 45 years (range 36-65 years) and the GHPA group was 49 (range19-76 years). The three most common symptoms presented in each group included headaches, acral enlargement, and facial changes. The mean tumor diameter and median KNOSP score for MGPA was 25 mm and 3, and GHPA was 15 mm and 1 (diameter p=0.011, KNOSP p=0.115). All patients underwent an endoscopic endonasal transsphenoidal approach (EETA) for resection. Hormonal remission was defined as age-appropriate normalization of IGF-1 at 6 weeks and was achieved post-operatively in 3/5 (60%) MGPA patients and 19/41 (45%) GHPA patients (p=0.652). Of the patients who achieved remission in the MGPA group, none had recurrence, while in the GHPA group four patients harbored tumor/hormonal recurrence. Mean follow-up time for MGPA patients was 9 months (range 3-17) and 34 for GHPA patients (range 4-73).
Table 1: GHPA and MGPA Comparison of Patient Demographics and Clinical Courses
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All statistical comparisons between groups were performed using a chi-squared or independent unpaired sample t-test. Raw totals, mean values, and percentages are indicated in each category under Characteristics.
Discussion:
We present our institutional experience in the management of patients with MGPAs and compare this rare PA subtype with GHPAs. There was no difference seen in the presentation and preoperative hormone panel, including IGF-1 elevation between both groups. However, the MGPA group tended to have larger tumors (p=0.009) and a higher degree of cavernous sinus invasion (p=0.110). EETA remains a safe and effective surgical technique for resection of MGPAs. Both groups had a similar hormonal remission rate postoperatively. The limitations of our study include the retrospective nature of the review, the small number of MGPA patients, and the relatively short follow-up in the MGPA group. Given the rarity of this tumor, a systemic review incorporating available literature is planned.