Chronic sclerosing sialadenitis or Küttner tumor is an unusual chronic inflammatory disease of the salivary gland that mimics a malignant neoplasm clinically because of presentation as a hard mass. The diagnosis can only be made histologically and is an underrecognized entity. Recent studies have shown important features that characterizes the disease mainly as an autoimmune reaction. The aim of this work is to report a case of a 40-year-old man, presenting with a three-year history of a painless, moderate sublingual mass related to a partial edentulism of the teeth 36 and 37. Functional evaluation revealed an awkward misplacement of the mass into the edentulous site. Clinical and radiographic procedures revealed a decreased salivary flow and no signs of remarkable pain or sialolithiasis. Sublingualectomy was performed and histopathological examination confirmed the presence of nonobstructive chronic sclerosing sialadenitis of the sublingual gland. The possible autoimmune reaction triggered by hidden (sequestered) antigens exposed by chronic masticatory trauma is discussed.