Association between serum prolactin and anterior pituitary dysfunction in pituitary stalk interruption syndrome: a retrospective study of 155 patients from a large tertiary medical center in China

Pituitary stalk interruption syndrome (PSIS) is a rare hypothalamic-pituitary disorder causing progressive anterior pituitary deficiency. Subtle early symptoms and unreliable sex hormone levels in prepubertal patients complicate diagnosis of anterior pituitary deficiency. This study aimed to investigate the association between serum prolactin (PRL) levels and anterior pituitary deficiency in PSIS patients, as well as its potential as a biomarker for complete anterior pituitary deficiency (CAPD). This retrospective study analyzed 155 patients with PSIS diagnosed and treated at the Chinese People’s Liberation Army General Hospital. We assessed the association between PRL levels and the severity of pituitary function deficits as well as testicular volume, and further evaluated its diagnostic value for CAPD. Among 155 patients with pituitary stalk interruption syndrome (89.03% male; mean age 21.76 ± 6.20 years), 88 cases (56.77%) had complete anterior pituitary dysfunction(CAPD), while 67 cases(43.23%) had partial anterior pituitary dysfunction(non-CAPD). Patients with CAPD exhibited higher serum prolactin (PRL) levels (median 13.37 µg/L [IQR 8.93–24.01] vs. 11.44 µg/L [IQR 7.08–15.32], p = 0.006), and PRL levels increased with the number of impaired pituitary axes (p = 0.002). For every 1 µg/L increase in PRL, the risk of CAPD increased by 9% (95% CI: 1.04–1.14, p < 0.001). When combined with age, the area under the curve (AUC) for PRL in predicting CAPD was 0.73 (95% CI: 0.65–0.81) in the overall patient group, and as high as 0.84 (95% CI: 0.71–0.97) in patients under 18 years old, indicating better diagnostic performance in younger patients. Serum PRL levels were negatively correlated with testicular volume (a key predictor of fertility function) (r = -0.33, p < 0.001). Elevated PRL levels correlate with the severity of anterior pituitary deficiency in PSIS, with higher diagnostic value for CAPD in patients under 18 years. Higher PRL levels correlates with reduced testicular volume. Not applicable.