title: Oral lichen sclerosus expressing extracellular matrix proteins and IgG4-positive plasma cells.
abstract: Lichen sclerosus (LS) is a mucocutaneous disease with uncommon oral involvement. The etiology is not yet well understood, but LS has been associated with autoimmune, genetic, and immunological factors. We report a 47-year-old man with LS that exhibited an asymptomatic white plaque with red patches on the maxillary alveolar mucosa extending to the labial mucosa. He had no other skin disease. Positive immunostaining for tenascin and scarcity of fibronectin suggested extracellular matrix reorganization. Elastin immunostaining indicated a reduction of elastic fibers. Immunoexpression of collagen IV in blood vessels and its absence in the epithelial basement membrane, together with diffuse MMP-9 immunoexpression, suggested altered proteolytic activity. Mast cell staining bordering areas of sclerosis indicated a possible role in the synthesis of collagen. IgG4 positivity in plasma cells suggested a role in the fibrogenesis. This is an unusual presentation of oral LS and we discuss immunohistochemical findings regarding cellular and extracellular matrix components.
authors.forename: Flavia Calo
authors.initials: FC
authors.lastname: De Aquino Xavier
authors.forename: Alisio Alves
authors.initials: AA
authors.lastname: Prates
authors.forename: Clarissa Araujo
authors.initials: CA
authors.lastname: Gurgel
authors.forename: Tulio Geraldo
authors.initials: TG
authors.lastname: De Souza
authors.forename: Rodrigo Guimaraes
authors.initials: RG
authors.lastname: Andrade
authors.forename: Eduardo Antonio
authors.initials: EA
authors.lastname: Goncalves Ramos
authors.forename: Luciana Maria
authors.initials: LM
authors.lastname: Pedreira Ramalho
authors.affiliation: Federal University of Bahia, Brazil.
authors.forename: Jean Nunes
authors.initials: JN
authors.lastname: Dos Santos
mesh_terms: D024141:Collagen Type IV / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000378:metabolism*; D018459:Lichen Sclerosus et Atrophicus / Q000378:metabolism* / Q000473:pathology; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D009059:Mouth Diseases / Q000378:metabolism*; D009061:Mouth Mucosa / Q000378:metabolism; D010950:Plasma Cells / Q000378:metabolism*; D019063:Tenascin / Q000378:metabolism
chemical_list: D024141:Collagen Type IV; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D007074:Immunoglobulin G; D019063:Tenascin; D020780:Matrix Metalloproteinase 9