Reproducibility of minor salivary gland biopsy reports in Sjögren's syndrome and its correlation with disease biomarkers.

Introduction/objective: Sjögren's syndrome (SS) is a systemic autoimmune disease that is challenging to diagnose. Although minor salivary gland biopsy (MSGB) is a useful ancillary study, different factors make its interpretation difficult. Also, the significance of distinct histopathological findings is unknown. We aimed to determine the concordance between pathologists and rheumatologists in interpreting the MSGB results, as well as the correlation between MSGB findings, paraclinical features, and SS diagnosis.

Methods: This descriptive retrospective study reviewed medical charts from 998 individuals from a single center where MSGBs had been performed. Rheumatologists interpreted biopsy reports from pathologists, and interobserver variability was calculated. Logistic regression using immunological parameters and histological findings was performed.

Results: We included 998 patients with a median age of 55 years (45-64 years); the majority of patients were females (n = 934, 93.6%). Chisholm and Mason's scoring system was the most frequently used scale (55.1%). There was a good correlation between pathologists and rheumatologists for diagnosing SS using MSGB findings (Cohen's kappa 0.91). We observed a strong association between interstitial plasmocytes and SS (OR 24, 95% CI 9.09-64.94, p = 0).

Conclusion: The MSGB is an essential tool for the diagnosis of SS. Although different factors may negatively affect its reproducibility, histological findings, such as interstitial plasmocytes, may predict the risk of developing SS. Key Points • We provide information based on 998 patients with suspected SS diagnosis. • Chisholm and Mason's scale is the most frequently used compared to Greenspan's and Tarpley's scales. • There is good correlation between pathologists and rheumatologists for the diagnosis of SS using MSGB.