Ultrasound-guided core needle biopsy and incisional biopsy of the parotid gland are comparable in diagnosis of primary Sjögren’s syndrome

Objectives: Salivary gland lymphocytic infiltrates are a hallmark of primary SS (pSS), but traditional biopsy techniques hold several disadvantages. Ultrasound-guided core needle (US-guided CN) parotid gland biopsy is minimally invasive and reliable for diagnosis of lymphoma in pSS. This proof-of-concept study aimed to explore this technique in the diagnostic work-up of pSS and is the first to address its value in a consecutive cohort independently of the presence of salivary gland swelling. Methods: Combined incisional and US-guided CN parotid biopsy was performed in 20 patients with suspected or confirmed pSS from the Belgian Sjogren's Syndrome Transition Trial (BeSSTT). Surface area and presence of a focus score (FS) of at least one, germinal centres and lymphoepithelial lesions were recorded. Results: Salivary gland tissue was interpretable in 19 patients. Fourteen patients had >= 4 mm(2) salivary gland tissue by both techniques, in four US-guided CN biopsies salivary gland tissue was = 4 mm(2) displayed a concordance of 90% for FS >= 1. Presence of lymphoepithelial lesions and germinal centres showed absolute concordance. Of four US-guided CN biopsies = 1 or germinal centres gave a sensitivity of 70% in incisional and of 69% in US-guided CN biopsy. Conclusions: US-guided CN biopsy of the parotid gland is at least equivalent to incisional biopsy of the parotid gland in the diagnostic work-up of pSS