Pituitary Gland Volume in Fibromyalgia Syndrome: A Case-Control Volumetric MRI Study

Fibromyalgia (FM) is a chronic pain syndrome frequently associated with neuroendocrine dysfunction and has been hypothesized to share pathophysiological mechanisms with conditions such as empty sella (ES) and intracranial hypertension. Data regarding pituitary morphology in FM remain limited. This study aimed to evaluate pituitary gland volume (PGV), pituitary gland height (PGH), and the frequency of ES in patients with FM using volumetric magnetic resonance imaging (MRI).

This single-center, prospective, cross-sectional study included 30 female patients with FM and 26 age-matched female controls. All participants underwent brain MRI using a 3-T scanner. Pituitary volumetric measurements were obtained through manual segmentation with Insight Segmentation and Registration Toolkit software. Inter- and intra-observer reliability were assessed using intraclass correlation coefficients. Group comparisons were performed using independent samples t-tests and analysis of covariance (ANCOVA), with statistical significance set at p < 0.05. Linear regression analysis was used to evaluate associations between variables.

The FM and control groups did not differ significantly in age or body mass index. Mean PGV was significantly higher in the FM group compared with controls (625.8 ± 115.2 mm³ vs. 519.5 ± 148.3 mm³), with a mean difference of 106.3 mm³ (95% CI: 35.9 to 176.7, p = 0.004), whereas PGH did not differ significantly. ES was identified in one participant in each group, with no significant difference in prevalence.

Patients with FM demonstrated increased PGV. ES was rarely observed in both groups. The biological and clinical implications of these findings warrant further investigation in larger cohorts integrating hormonal and volumetric imaging analyses.