Abstract
PURPOSE: To characterize the clinicopathological features and metabolic profiles of silent growth hormone pituitary adenomas (SGH-PAs). METHODS: The single-center retrospective study identified SGH-PAs from 1387 surgically treated non-functioning PAs at Peking Union Medical College Hospital (2019-2023). Controls included 407 consecutive cases with non-functioning gonadotropin pituitary adenomas (NFG-PAs) and 90 age and gender-matched acromegaly patients. Baseline and postoperative hormonal assessments, pituitary imaging features, pathological classification, metabolic comorbidity, and follow-up outcome were collected and analyzed. RESULTS: 45 cases of SGH-PA (3.2%) were identified from 1387 non-functioning PAs. The pathological subtypes included 18 (40%) acidophil stem cell adenomas, 11(24%) immature PIT1-lineage tumors, 5 sparsely granulated GH tumors, 5 mammosomatotroph tumors, 4 mature plurihormonal PIT1 lineage tumors, and 2 plurihormonal pituitary tumors. Compared to controls, SGH-PAs showed modestly elevated proliferation (median Ki-67 3% vs. 2% in both acromegaly [p = 0.002] and NFG-PAs [p = 0.011]) without outstanding increases in tumor invasiveness (Knosp 3-4: 20-30% across groups) at baseline or 2-year recurrence. Baseline metabolic comorbidities paralleled NFG-PA profiles for hypertension (22%) and diabetes (8.9%), with reduced dyslipidemia prevalence (17.8% vs. 33.4%, p = 0.049). No case of SGH-PAs transforming into acromegaly was confirmed during 77 person-years of follow-up. CONCLUSIONS: SGH-PAs represent approximately 3% of nonfunctioning PAs undergoing surgery. Multiple anterior pituitary hormones are commonly co-expressed. These tumors may be more proliferative, but the baseline aggressiveness in radiology and short-term recurrence rates are similar.