This article presents the case of an IgG4-related disease in a patient with clinical signs of a malignant tumor of the oral cavity. After excluding the suspicion of a malignant lesion, vasculitis and various infectious diseases were ruled out. Finally, due to further immunohistochemical studies, IgG4-related disease was diagnosed.
Keywords: IgG4; Immunoglobulin G; Neoplasms; Oral cavity; Vasculitis.