Diagnostic value of labial minor salivary gland biopsy for Sjögren's syndrome: a systematic review

Objectives: To assess the diagnostic value of minor salivary gland biopsy (MSGB) for primary Sjögren's syndrome (pSS).

Methods: Systematic review of studies retrieved from PUBMED and EMBASE using the terms 'salivary glands' AND 'Sjögren's syndrome' AND 'biopsy', conducted in patients with suspected pSS, and defining positive biopsies as a focus score (FS)≥1. Sensitivity and specificity of MSGB were abstracted from the articles or calculated when possible.

Results: Of 238 publications identified initially, 9 were included in the study. MSGB sensitivity ranged from 63.5% to 93.7% and specificity from 61.2% to 100%. Specificity was >89% in six studies. An attempt to separate patients with and without pSS without using MSGB findings or via clinical re-evaluation was made in only two studies, in 73 and 120 patients, respectively, with sicca syndrome in the first study and suspected pSS in the other. The reference standard for diagnosing pSS was a set of criteria that did not include MSGB in the first and patient re-evaluation by three experienced rheumatologists who were aware of MSGB findings in the other. In these studies, sensitivity was 63.9% and 85.7% and specificity was 91.9% and 89.7%, respectively.

Conclusions: Few published studies have evaluated the diagnostic usefulness of MSGB in pSS. Only two studies used a methodology that precluded circular reasoning. Our study indicates a lack of information about the diagnostic value of MSGB. Specificity and positive predictive values (PPV) are high and sensitivity is variable.