BACKGROUND: Lichen planus is a relatively common chronic inflammatory disease affecting skin and mucous membranes, separately or together. It frequently involves the oral cavity, with or without concomitant cutaneous compromise. Microscopically, while skin presents well characteristic aspects, oral mucosa can present variations related to local characteristics of the mucosa in the oral cavity. OBJECTIVES: To compare histopathological alterations of oral lichen planus and cutaneous lichen planus with the study of the inflammatory infiltrate components. METHODS: 59 biopsies (29 of OLP and 30 of CLP), formalin-fixed, paraffin-embedded were studied. Semi-quantitative analysis of both epidermal and dermal alterations was performed using the hematoxylin-eosin and periodic acid-Schiff stains. RESULTS: For CLP the classic aspects of orthokeratosis, wedge shaped hypergranulosis and saw tooth rete ridges were observed. Such aspects differ from those of OLP in which orthokeratosis and thickened granular layer happen less frequently; instead, acquisition of those layers is observed in places where they are usually absent. Basal cell vacuolar alteration and effacement of the epithelium-conjunctive limit prevailed in both locations (skin and oral mucosa) and lymphocytes and histiocytes were the inflammatory cells present in all cases. CONCLUSIONS: Classic alterations as compact orthokeratosis, wedge shaped hypergranulosis, saw tooth rete ridges acanthosis and basal cell vacuolar alteration associates to lymphocytes in superficial band-like pattern are diagnostic of CLP. However, for OLP, the particular own characteristics of oral mucosa in the biopsied place should be considered; also, subtler alterations of horny (light orthokeratosis) and granular (presence where it is usually absent) layers should be valued . Wedge shape pattern of hypergranulosis is rarely seen in OLP. Saw tooth rete ridges acanthosis is not frequently seen in OLP, however, basal cell vacuolar alteration is always present and associated to band-like lymphocitic infiltrate. Plasma cells can accompany lymphocytes in OLP, however, they are absent in CLP.
Lichen planus; Oral; Cutaneous; Histopathology
