Abstract: PURPOSE: To study the ultrasonic manifestation of IgG4-related sialadenitis, and improve sonographers’ understanding of this disease. METHODS: Based on the clinical serological test and histopathologic diagnosis, the features were evaluated by sonography in 25 cases of IgG4-related sialadenitis, including the shape and border of the gland, internal echo texture, presence and distribution of vascularity, duct dilatation, presence/absence of calculi and submandibular lymph nodes. The changes on ultrasonography in 14 patients with IgG4-related sialadenitis before and after steroid treatment were evaluated. RESULTS: There were 20 men and 5 women ranging between 42-89 years old with an average age of 64.5 years old. The sites of involvement were submandibular gland (20 cases) and parotid gland (5 cases). Of the 10 patients with diffuse involvement, the lesions showed bilateral symmetrical distribution in 9 patients and unilateral involvement in 1 patient with multiple hypoechoic lesions against a heterogeneous background. The ducts were dilated in 3 patients, and had calculus in 2 patients. Doppler sonography in all patients with diffuse involvement of the gland showed prominent intraglandular vessels. Of the 15 patients with focal involvement, 14 patients showed unilateral involvement and only one showed bilateral involvement of the submandibular gland with hypoechoic heterogeneous. The vessels showed a radial pattern within the lesions. There were definite submandibular lymph nodes involvement by IgG4-related disease in 4 of the 8 patients. After steroid treatment, the prominent sonographic feature of IgG4-related sialadenitis gradually receded. CONCLUSIONS: Sonologist must be aware of sonographic appearances in patients with IgG4-related sialadenitis, which can help correct diagnosis and treatment.

Key words: IgG4-related sclerosing disease, Ultrasound, Submandibular gland, Parotid gland, Submandibular lymph nodes