Minor salivary gland biopsy and Sjögren's syndrome: comparative analysis of biopsies among different Italian rheumatologic centers.
OBJECTIVE
The minor salivary gland biopsy (MSGB) is widely considered an important component of the diagnostic algorithm of primary Sjögren's syndrome (pSS) and is mentioned in all the classification criteria sets for the disease. The aim of this study, coordinated by the Italian Society of Rheumatology, was to verify the inter-observer agreement on the evaluation of MSGB among different experienced Italian rheumatologic centres, in order to better standardise the diagnostic methodology.


METHODS
Seven centres participated in the study, providing a total of 50 MSGB samples. Each center blindly classified all the samples according to the Chisholm and Mason (CM) grading. The results were collected and analysed.


RESULTS
The inter-observer agreement was satisfactory when the samples were stratified as consistent and non-consistent with the final diagnosis of pSS (median κ =0.75; mean κ =0.70). Nonetheless, significant discrepancies in the histopathologic evaluation of MSGB emerged when the agreement was assessed on the single scores. Considering the modal CM grading for each sample as the correct grading, upon re-examination, a potential bias in the final clinical diagnosis was detected in 7 out of 50 samples.


CONCLUSIONS
This study has shown significant discrepancies in the evaluation of MSGB among different rheumatologic centres in the same country. Greater standardisation of the procedure is clearly necessary, both to improve the diagnostic performance and scientific communication.
Clinical Immunology Unit, Department of Internal Medicine, University of Pisa, Pisa, Italy. a.tavoni@int.med.unipi.it
Antonio Gaetano
AG
Tavoni
Chiara
C
Baldini
Walter
W
Bencivelli
Luigi
L
Cavazzini
Michele
M
Covelli
Salvatore
S
De Vita
Roberto
R
Caporali
Roberto
R
Gerli
Michele
M
Giansanti
Marcello
M
Govoni
Valentina
V
Donati
Carlo Maurizio
CM
Montecucco
Patrizia
P
Morbini
Francesco Paolo
FP
Pilato
Leonardo
L
Resta
Cathryn Anne
CA
Scott
Marta
M
Mosca
Claudio
C
Vitali
Stefano
S
Bombardieri
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000592:standards; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012219:Rheumatology / Q000379:methods* / Q000592:standards; D012470:Salivary Glands, Minor / Q000473:pathology*; D012720:Severity of Illness Index; D012859:Sjogren's Syndrome / Q000473:pathology*; D062606:Tertiary Care Centers / Q000592:standards; D055815:Young Adult