Chronic sclerosing sialadenitis of the sublingual gland: case report and literature review

Chronic sclerosing sialadenitis (CSS) is a chronic inflammatory condition of uncertain etiology, primarily affecting the submandibular glands. It has recently been proposed that CSS belongs to the immunoglobulin G4 (IgG4)-related disease spectrum, although the exact relationship between these two entities requires further elucidation. Our aim is to present a case of bilateral CSS of the sublingual glands and discuss the possible underlying pathogenetic mechanisms. A 66-year-old woman presented with a 7-month history of an asymptomatic firm swelling of the floor of the mouth. Clinically, a diffuse, multinodular swelling of elastic to firm consistency was observed across the sublingual folds bilaterally. An incisional biopsy revealed a lymphoplasmacytic infiltrate with lymphoid follicle formation, along with acinar degeneration, fibrosclerosis and ductal dilation. Immunohistochemical investigation ruled out lymphoproliferative diseases revealing a polyclonal lymphoplasmacytic population with only a few scattered IgG4-positive plasma cells. IgG4 serum levels were also normal. No treatment was administered with progressive spontaneous resolution of the swelling and no evidence of recurrence at 2 years follow-up. CSS is a benign salivary gland disorder, which, at least in a subset of cases, may represent an IgG4-associated disorder. Therefore, immunohistochemical evaluation of the IgG4/IgG plasma cell ratio and the IgG4 serum levels is a recommended investigation in the diagnostic work-up of CSS cases.