Increased diagnostic accuracy of the labial gland biopsy in primary Sjögren's syndrome when multiple histopathological features are included

OBJECTIVE: To evaluate the diagnostic accuracy of the labial salivary gland biopsy based on multiple histopathological features in patients with suspected primary Sjögren's syndrome (pSS).

METHODS: Patients from a diagnostic sicca cohort with clinically suspected pSS, who underwent a labial gland biopsy, were included. Patients were categorized as pSS or non-SS sicca based on vignettes scored by an expert panel. Labial gland biopsies were analyzed for the presence of four histopathological features: focus score (FS)≥1, (pre-)lymphoepithelial lesions, IgG plasma cell shift and germinal centers. Sensitivity and specificity of histological features were calculated, and the optimal cut-off value for the number of histopathological features needed to diagnose pSS was determined with ROC analysis.

RESULTS: 38 patients were categorized as pSS and 65 as non-SS sicca. In labial gland biopsies of pSS patients, prevalence of FS≥1 was 82%, followed by 68% for (pre-)lymphoepithelial lesions, 63% for plasma cell shift and 24% for germinal centers. Although FS≥1 showed the highest sensitivity for pSS (82%), specificity was higher for the other three features (98-100%). The presence of ≥2 (out of 4) histopathological features had almost comparable sensitivity to FS alone, but specificity increased with 12% to 100%. For fulfillment of ACR-EULAR criteria, specificity increased from 84% to 95% when an abnormal biopsy was defined by the presence of ≥2 histopathological features instead of FS≥1 only.

CONCLUSION: The diagnostic accuracy of the labial gland biopsy increases when other histopathological features besides FS are taken into account, by reducing the number of false positive biopsies. This article is protected by copyright. All rights reserved.