Thymic hyperplasia in patients with acromegaly: imaging-based assessment and clinical implications.

Abstract

Objective: We aimed to compare thymus visibility and volume in patients with acromegaly to those of controls, and to evaluate the correlation between growth hormone (GH), insulin-like growth factor-1 (IGF-1) levels, and thymus volume.

Subjects and methods: This cross-sectional case-control study included 66 patients with acromegaly who underwent thoracic computed tomography scans. An age- and sex-matched control group of 65 trauma patients without comorbidities was selected. All thoracic computed tomography scans were reassessed to measure thymus volume using imaging software. Comparisons of thymus volume and assessment of correlation with GH and IGF-1 levels were performed.

Results: The acromegaly group (28F/38M) and the control group (27F/38M) had similar sex and age distributions. The thymus was more frequently detectable in the acromegaly group (80.3%) compared to controls (44.6%; p = 0.001). Thymus volume was significantly higher in the acromegaly group (13.1 cm3 [9.7-18.7]) than in the control (10.3 cm3 [4.6-12.3]; p = 0.013). Serum IGF-1 levels were nearly significantly higher in acromegalic patients with a visible thymus compared to those without (visible thymus: 608.5 ng/mL [377.6-921.8]; non-visible thymus: 440.5 ng/mL [201.5-596]; p = 0.054). However, no significant differences were found in GH and IGF-1 upper limit of normal levels. No correlation was found between thymus volume and other parameters.

Conclusion: Patients with acromegaly have larger and more frequently visible thymus glands than controls. When a mass is detected in the anterior mediastinum, acromegaly should be considered, especially before invasive procedures.