Prolactin Co-Staining in Acromegaly: Clinical Features and Long-Term Outcomes

Objective: To compare the clinical presentation, tumor characteristics, surgical remission, and long-term biochemical control between patients with growth hormone (GH) and prolactin (PRL) co-staining pituitary adenomas (GH&PRL-PAs) and those with merely growth hormone–secreting pituitary adenomas (GH-PAs).

Methods: This retrospective, single-center cohort included adults with acromegaly who underwent transsphenoidal surgery between 2000 and 2023. GH&PRL-PAs were defined by positive immunostaining for both GH and PRL. Predictors of surgical remission were assessed using multivariable logistic regression, and determinants of last-visit insulin-like growth factor 1 (IGF-1) were evaluated using multivariable linear regression.

Results: Among 358 patients, 125 patients (34.9%) were classified as GH&PRL-PAs. Median follow-up was 103 [51-144] months. Women comprised 59.2% of the cohort; female sex was similarly distributed between GH&PRL-PAs and GH-PAs (54.4% vs. 61.8%, P = .174). GH&PRL-PAs had lower GH levels at diagnosis (6.3 [3.2-23] vs. 12.4 [5-29.7] ng/mL, P = .023), postoperatively (1.2 [0.3-3.9] vs. 2.2 [0.3-3.9] ng/mL, P = .021), and at the last visit (1.2 [0.5-3.3] vs. 1.4 [0.6-3.6] ng/mL, P = .006). Insulin-like growth factor 1 levels were comparable at diagnosis and the last visit. Tumor size and Ki-67 index were similar, whereas cavernous sinus invasion was less frequent in GH&PRL-PAs (39.8% vs. 53.1%, P = .027). Surgical remission neither differed significantly between groups (37.6% vs. 28.8%, P = .087) nor did active disease at the last visit (17.6% vs. 17.2%, P = .918). Prolactin staining was not an independent predictor of surgical remission or last-visit IGF-1.

Conclusion: Growth hormone and prolactin co-staining pituitary adenomas show a distinct hormonal profile, but PRL co-staining alone does not appear to determine surgical or long-term biochemical outcomes.

Cite this article as: Sulu C, Tanrıöver N, Sarıçoban CT, Gazioğlu N, Kadıoğlu P. Prolactin co-staining in acromegaly: clinical features and long-term outcomes. Cerrahpaşa Med J 2026, 50, 0096, doi: 10.5152/cjm.2026.26096.