Shear wave elastography as a new method to identify parotid lymphoma in primary Sjogren Syndrome patients: an observational study.

Parotid non-Hodgkin lymphoma (NHL) in primary Sjogren syndrome (pSS) has no specific biomarker for diagnosis. Salivary glands ultrasound (US) is largely used, but its contribution in detecting parotid NHL has not been established. The aim of our study was to determine the added value of bidimensional shear wave elastography (2D-SWE) in pSS diagnosis and to determine its accuracy in identifying parotid NHL. Grey-scale US (GSUS) and 2D-SWE of salivary glands were performed in 35 patients with pSS and 35 healthy controls. The GSUS scores were calculated and the mean of three SWE consecutive measurements was used to appreciate the gland stiffness. SWE increase the diagnostic rate at a cut-off of 6.45 kPa (from 88.6 to 94.2%, p 20 mm (all glands), traced gland area over 5 cm(2) (all glands), parotid US score greater than 13 (in 68.75% of the glands), and high stiffness (elasticity modulus 13.9 +/- 4.08 vs 6.32 +/- 2.24) (all p 0.05). 2D-SWE had added value for pSS diagnosis in cases where GSUS aspect is normal or nonspecific. The higher stiffness of parotid NHL can be used for early diagnosis, biopsy guidance, and, possible, for treatment monitoring.