Ultrasonographic scores and parotid histopathology in Sjögren's disease: challenges in lymphoma identification.

Objectives: The role of major salivary gland ultrasound (SGUS) in evaluating Sjögren's disease (SjD) continues to be debated. This study aims to assess the effectiveness of two SGUS scores (OMERACT and Hocevar et al.) in identifying lymphoma in SjD patients. A secondary aim is to explore the correlation between SGUS findings and histological characteristics of the parotid salivary glands.

Methods: Consecutive adult SjD patients with a clinical indication for parotid gland biopsy between September 2018 and October 2023 were included. Ultrasound images were anonymised and assessed according to the OMERACT and Hocevar et al. scores. The histological assessment performed by the pathologist included the evaluation of lymphoma presence, focus score (FS), lymphoepithelial lesions (LELs), germinal centres (GCs), multiple focal lymphocytic sialadenitis/lymphoepithelial sialadenitis (MESA/LESA), and features of non-specific sialadenitis.

Results: Among the 57 patients included in the study, 24 (42%) were diagnosed with lymphoma. Neither the OMERACT nor the Hocevar et al. score were effective in identifying lymphoma (OMERACT score: odds ratio 1.10, 95% CI: 0.91-1.34; p=0.305; Hocevar et al. score: odds ratio 1.03, 95% CI: 0.97-1.10; p=0.300). In the remaining 33 patients without lymphoma diagnosis but at higher risk of lymphoma development, regression analysis showed significant associations between ultrasound scores and histopathological features. LELs were linked to higher OMERACT (β=3.57, 95% CI:1.53-5.61; p=0.001) and Hocevar et al. scores (β=8.16, 95% CI: 1.45-14.87; p=0.019). Additionally, the FS was correlated with both OMERACT (β=0.26, 95% CI: 0.09-0.43; p=0.004) and Hocevar et al. scores (β=0.57, 95% CI: 0.03-1.12; p=0.040).

Conclusions: The current SGUS scores seem not to allow identifying lymphoma in SjD patients with high clinical suspicion. However, the correlation between advanced histological lesions and SGUS scores raises the opportunity of developing new SGUS scores with a prognostic rather than diagnostic or classificatory significance.