Clinical and immunopathologic findings in oral lichen planus pemphigoides

Lichen planus pemphigoides (LPP) is a rare, acquired, immunobullous disorder of skin that occasionally involves oral mucous membranes. Clinical, histologic, and immunopathologic findings of the oral manifestations of LPP are described. Clinical features are lichenoid striae, erosions, and ulcerations involving gingiva and buccal mucosae. Histopathologic features are similar to those of ora lichen planus. Direct immunofluorescence demonstrates linear deposits of immunoglobulin G and complement component C3 along the basement membrane with fibrillar deposits of fibrin at the epithelial/lamina propria junction. Fluorescence overlay antigen mapping and laser scanning confocal microscopy of the biopsy specimen exhibits colocalization of in situ antibodies with β4 integrin, a marker of the keratinocyte basal plasma membrane and upper lamina lucida, consistent with the location of the bullous pemphigoid antigens. This case report describes a case of LPP that presented exclusively as an oral condition. Lichen planus pemphigoides should be considered in the clinical differential diagnosis of vesiculoerosive oral mucosal diseases.