Lacrimal gland herniation in Graves ophthalmopathy: a simple and useful MRI biomarker of disease activity

Background: Lacrimal gland (LG) involvement in patients with Graves ophthalmopathy (GO) has been considered as a potential cause of the associated GO symptoms and different studies demonstrated the LG involvement in patients with GO than healthy controls. The aim of this study was to evaluate LG involvement, through measurement of its herniation, using a magnetic resonance imaging (MRI) index, in patients with different GO activities. Methods: Thirty-two consecutive Caucasian patients affected by GO were enrolled and grouped in group A (16 with inactive GO, CAS < 3) and B (16 with active GO, CAS ≥ 3) according to their GO activity. All patients underwent clinical-endocrinological assessment, a complete ocular evaluation, and orbital MRI examination. Results: No difference was found between the hormonal parameters, thyroid ultrasound-derived parameters, and thyroid-stimulating hormone (TSH) receptor (TSH-R) antibodies (TRAb) levels in group B and those in group A. The LG herniation (LGH) measurement evaluated by MRI was significantly higher in group B for both right (10.1 (7.3–17) vs. 7 (0–3.4) mm; p = 0.004) and left (8.5 (6.6–13) vs. 5.8 (0–12) mm; p = 0.026) eye than group A. A positive correlation was found between TRAb and LGH herniation (Rho 0.462, p = 0.009). Conclusions: Measurement of LGH seems to be a good marker of the disease and GO activity. Key Points: • Lacrimal gland herniation is a simple index related to disease activity • Lacrimal gland herniation is correlated to TRAb levels • Lacrimal gland evaluation could be useful to differentiate active from inactive Graves ophthalmopathy in an early stage of disease.