[Clinical and imaging characteristics and etiology of 544 cases with chronic sialadenitis]

To investigate the etiology of chronic sialadenitis, and to analyze their clinical and imaging characteristics.

This retrospective analysis reviewed the clinical and imaging data of patients with chronic sialadenitis who underwent sialendoscopy at the Peking University Hospital of Stomatology between January 2021 and August 2023.

(1) with a history of recurrent swelling of major salivary glands; (2) complete medical records with detailed information about potential causes; (3) sialography images were available; and (4) patients had undergone interventional endoscopy.

(1) salivary stones; (2) juvenile recurrent parotitis; (3) IgG4-related sialadenitis; (4) Sjögren syndrome; and (5) neoplastic diseases. Based on the latest research results and clinical data, chronic sialadenitis was classified into radioactive iodine-induced sialadenitis (RAIS), allergy-related sialodochitis (ARS), adult chronic recurrent parotitis (ACRP), sialadenosis with sialodochitis, and idiopathic sialadenitis. Idiopathic sialadenitis was defined as a type of chronic sialadenitis with duct stenosis of unknown etiology (allergic causes, autoimmune disorders, radioactive iodine exposure, history of "parotitis" in childhood, etc.). The proportions of five types of sialadenitis were calculated, and their relationships with age, gender, type of affected glands, number of affected glands, duration of symptoms, and imaging characteristics were statistically analyzed.

A total of 544 consecutive patients diagnosed with chronic sialadenitis were enrolled in this study. They consisted of 192 males and 352 females, and their ages ranged from 14 to 83 years [mean age: (47.44±13.52) years]. Idiopathic sialadenitis accounted for the largest proportion (71.7%, 390 cases), followed by ARS (12.5%, 68 cases), RAIS (6.4%, 35 cases), ACRP (4.8%, 26 cases), and sialadenosis with sialodochitis (4.6%, 25 cases). Among the 2 176 available glands of the 544 patients, 1 120 (51.5%) glands were affected, including 880 (78.6%) parotid glands and 240 (21.4%) submandibular glands. These five types of sialadenitis exhibited significant differences in gender, age, type and number of affected glands, and duration of symptoms (P < 0.05). Among them, RAIS patients showed the lowest male to female ratio (male ∶ female=1 ∶ 4.83), ARCP patients were the youngest [(32.50±8.60) years], and RAIS and ARS patients had relatively higher number of affected glands. Sialography showed ductal atresia in 23.2% of affected glands with ARIS, "snowflake" pattern in 46.5% of affected glands with ARS, "punctate and globular" ectasia of terminal ducts in 80.4% of affected glands with ARCP, and clustered branch ducts in 71.4% of affected glands with sialadenosis with sialodochitis. Moreover, stenosis and/or dilatation of the main and branch ducts represented the most typical sialography appearance of idiopathic sialadenitis.

Idiopathic sialadenitis, RAIS, ARS, ACRP, and sialadenosis with sialodochitis are the five common types of chronic sialadenitis. Among these, idiopathic sialadenitis is the most common type of chronic sialadenitis. Clarification of the etiology, clinical manifestations and imaging characteristics of chronic sialadenitis is important for clinicians to develop personalized treatment plans and improve treatment outcomes.