Reliability of histopathological salivary gland biopsy assessment in Sjögren's syndrome: a multicentre cohort study.

OBJECTIVE: The aim of this study was to assess intraobserver and interobserver reliability of minor salivary gland biopsy (MSGB) in SS. METHODS: All MSGBs available from the Tolerance and Efficacy of Rituximab in Primary Sjögren's Syndrome (TEARS) study were subjected to a standardized blinded assessment by a single specifically trained pathologist twice at a 2 month interval; both the Chisholm-Mason (CM) grade and the focus score (FS) were determined. Baseline histopathological reports by local pathologists at each study centre were compared with the first standardized blinded assessment. Agreement was assessed for the dichotomized FS (dFS) and dichotomized CM (dCM) grade, as well as for nine other histopathological features. RESULTS: Eighty-nine MSGBs were studied. Intraobserver κ values were 1 for dFS, 0.80 for dCM, 0.67 for germinal centre-like structures, 0.44 for fibrosis and 0.29 for confluent foci. Most of the local histopathological reports based their diagnosis on the CM grade, although the FS was often reported or the data needed to determine it were provided. Interobserver agreement κ values were 0.71 for dFS, 0.64 for dCM, 0.46 for focal lymphocytic sialadenitis, 0.42 for non-specific chronic inflammation and 0.16 for fibrosis. CONCLUSION: Although FS reliability was good, disparities were noted in the assessment methods used by local pathologists. The protocol for FS determination was not followed routinely, with the result that the FS was often overestimated. Germinal centre-like structures, which predict lymphoma, showed good reliability but were inconsistently reported.

B-cell and T-cell quantification in minor salivary glands in primary Sjögren's syndrome: development and validation of a pixel-based digital procedure.

BACKGROUND: Evaluating lymphocytic infiltration of minor salivary gland biopsy in primary Sjögren's syndrome is challenging. We developed and evaluated a digital method for quantifying B and T lymphocytes in whole minor salivary gland biopsy slides. METHODS: Minor salivary gland biopsies were immunostained with anti-CD20/anti-CD3 antibodies using red/brown chromogens. Slides were digitised and spliced into mosaics of smaller JPEG format images in which red and brown pixels were counted. ImageJ Cell counter was used for validation. Agreement between the digital and manual methods was evaluated using Bland-Altman plots and the interclass correlation coefficient. External validation relied on the Chisholm-Mason, Tarpley, and focus-score methods. RESULTS: Of 62 minor salivary gland biopsy slides, 61.3 % had a Chisholm-Mason grade ≥ III or a focus score ≥1. The number of pixels correlated well with manual cell counts (r = 0.95 for red pixels vs. B cell count and r = 0.91 for brown pixels vs. T cell count). Interclass correlation coefficients between digital and manual counts were excellent (0.92 for B/T cells). B-cell proportion showed a significant positive correlation with the focus score (Spearman's coefficient 0.463, p < 0.0001). Median B-cell proportion was lower in minor salivary gland biopsies with Chisholm grades I-II (2.5 % (0.2-13.9)) than III-IV (30.0 % (15.5-45.2)) and increased with Tarpley's class (1, 2.2 % (0.2-6.6); 2, 27.2 % (13.0-38.9); and 3-4, 48.5 % (29.4-56.4); p < 0.001 for all comparisons). Minor salivary gland biopsy B-cell proportion was also significantly correlated with several markers of clinical and biological activity of the disease, especially with markers of systemic B-cell hyperactivation. CONCLUSION: The digital procedure proved accurate compared to the reference standard, producing reliable results for whole tissue sections. TRIAL REGISTRATION: ClinicalTrials.gov [ NCT00740948 ]. Registered 22 August 2008.

[Soft tissue myoepithelioma, a rare tumor. A case report]. / Le myoépithéliome des tissus mous, une tumeur rare. A propos d'un cas.

Myoepithelioma of soft tissues is a rare and under-recognized tumor. We report a case of a myoepithelioma arising in the soft tissue of the wrist in a 37-year-old man. This 3cm, nodular, well circumscribed tumor consisted of a mixture of spindle and epithelioid cells in a fibrous or focally myxoid stroma. Nuclear atypia were mild and mitotic activity was 1 mitotic figure per 10 high-power fields. No tubular epithelial structure was found. The tumoral cells expressed cytokeratin (KL1) and S-100 protein. Smooth muscle actin and desmin were negative. The excision was complete. At 5 months, no recurrence was noted. Myoepithelioma of deep soft tissue has a predilection for extremity involvement. It has to be differentiated from extraskeletal myxoid chondrosarcoma, parachordoma and synovial sarcoma. Most of myoepitheliomas are benign. However, metastasis may occur in a minority of cases.