IgG4-related sialadenitis: IgG4 is helpful, but biopsies are still crucial

[Establishment and application of new techniques for submandibular gland preservation]

The saliva secreted from submandibular gland (SMG) accounts for 60%-65%. It plays an important role in maintaining the human function of swallow, digestion, testing, speech, protection of oral mucosa, and prevention from dental carries. The SMG is frequently resected during the treatment for various kinds of oral and maxillofacial diseases, resulting in xerostomia and decreased quality of life. During the past 15 years, Research Center of Salivary Gland Diseases in Peking University School and Hospital of Stomatology conducted a series of studies on new techniques for preservation of SMG and achieved remarkable results. The clinicopathologic and imaging characteristics of IgG4-related sialadenitis (IgG4-RS) were clarified based on systematic studies. The results of studies on the pathogenesis of IgG4-RS showed that unbalance of inflammatory factors mediated the abnormality of secretion of SMG. IL-4 participates in occurring and development of glandular fibrosis of SMG. Regulation of tumor necrosis factor α (TNF-α) and cleaning of senescent cells might be taken as the targets for treatment of IgG4-RS. The combination of glucocorticoid and steroid-sparing agents showed effective results for treating IgG4-RS, clinical remission was achieved in all the patients, serum IgG4 levels decreased, and salivary gland secretion significantly increased. Sialoendoscopy-assisted sialolithectomy was applied in the treatment of about 1 000 cases with submandibular hilar calculi with a success rate of more than 90%. Transfer of SMG was used for prevention from radiation-induced xerostomia in the patients with head and neck carcinoma. SMG was transferred to the submental region before radiotherapy and was kept away from the ra-diation field. The results of prospective clinical controlled study showed this technique could effectively preserve the function of SMG and prevent from xerostomia. Based on the micro-anatomical study on the blood vessels and ducts of SMG, partial sialoadenectomy was applied for treatment of benign tumors in the SMG. A clinical controlled study confirmed its safety for control of the tumors and its advantage of preservation of SMG function. The studies on the involvement of SMG in oral squamous cell carcinoma (OSCC) provided the anatomical and histopathological basis for preservation of SMG during neck dissection for early cases with OSCC. A innovated surgical modality "four preservations including SMG" was used during the neck dissection for the early cases with OSCC. A prospective randomized clinical controlled study confirmed its safety, feasibility, effectiveness for control of the carcinoma, and advantages of preservation of SMG function.

Imaging of IgG4-related disease of the head and neck

IgG4-related disease is a systemic, inflammatory disorder typically involving multiple organ systems. Several eponymous conditions described previously in the clinical and radiology literature are now recognised to be part of the IgG4-related disease spectrum. This includes multiple manifestations in the head and neck region, which are the subject of this review. Imaging can occasionally suggest the specific diagnosis of IgG4 disease. More commonly, it will be included in a limited differential diagnosis that requires clarification with the aid of image-guided biopsy. There are strict histopathological criteria for the diagnosis of IgG4-related disease.

Differential diagnosis of IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis

Our aim was to differentiate IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis by analysing clinical, radiographic, and pathological features. Fifty-five patients, 50, and 50 were enrolled, respectively and their baseline characteristics and serological, sialographic, and pathological findings compared. The male:female ratio for IgG4-related sialadenitis was 1:1.2 for primary Sjögren syndrome 1:15.7, and for chronic obstructive submandibular sialadenitis1:0.92. Numbers with enlarged salivary glands were 55, 16, and 50; with xerostomia 26, 48, and 0; with a history of allergy 26, 4, and 6, and with coexisting systemic disease 12, 19, and 0 (p=0.14). Mean (SD) serum IgG4 concentrations were 109.1 (97.9), 4.9. (1.9) g/L, and 5.3 (1.6) g/L, p<0.001 in all cases. Sialography showed enlargement of the gland, dilatation of the duct, and slightly decreased secretory function in IgG4-related disease; obvious sialectasia and decreased secretory function in Sjögren syndrome; and dilatation of Wharton's duct and filling defects in obstructive sialadenitis. Histopathological examination showed lymphoplasmacytic infiltration with storiform fibrosis, lymphoplasmacytic inflammation and lymphoepithelial lesions, and dilatation of the duct with epithelial metaplasia in the three groups, respectively. The number of IgG4-positive plasma cells was 123 (45)/HPF, 8 (3)/HPF, and 5 (4)/HPF, while the IgG4-/IgG-positive cell ratio was 71.7 (13.9)%, 4.6 (2.5)%, 18.9 (19.7)%, respectively (p<0.001). The three conditions have different clinical, radiographic, and pathological features that provide important clues to the differential diagnosis. Serological and histological tests are important, and comprehensive consideration is necessary.