Reflectance confocal microscopy as a new tool in the in vivo evaluation of desquamative gingivitis: patterns in mucous membrane pemphigoid, pemphigus vulgaris and oral lichen planus

Abstract

Background Desquamative gingivitis refers to a clinical manifestation associated with several mucocutaneous disorders. The most common are mucous membrane pemphigoid, pemphigus vulgaris and lichen planus. Their specific diagnosis is better established by histopathological and immunofluorescence evaluation. Objectives To examine cases of desquamative gingivitis using reflectance confocal microscopy (RCM) and compare the findings with those of normal gingiva. To compare RCM findings in desquamative gingivitis with conventional histopathology of the biopsied lesions, in order to establish criteria for this noninvasive diagnostic technique. Methods A total of 25 cases of suspected mucous membrane pemphigoid, pemphigus vulgaris and lichen planus were included. RCM was performed on the gingiva of a healthy person and on gingival lesions. All lesions were biopsied in order to perform a RCM–histopathological correlation. Results Reflectance confocal microscopy examination of the gingival lesions suspected to be mucous membrane pemphigoid revealed a separation at the level of the dermal–epidermal junction, filled with small, bright structures interpreted as blood cells. Histopathological and immunofluorescence findings confirmed the diagnosis. For pemphigus vulgaris, RCM features were intraepithelial clefts with round, detached cells interpreted as acantholytic keratinocytes, similar to the histopathological features. Hyperkeratosis and spongiosis associated with infiltration of inflammatory cells, seen as small, bright cells intermingling with the honeycomb keratinocyte epithelial structure, were seen in lichen planus. Mildly bright, round structures interpreted as necrotic keratinocytes and mildly bright, stellate structures, interpreted as melanophages, were also seen in the dermis. These features were present on histopathology, confirming the diagnosis of lichen planus. Conclusion We propose that RCM is a useful tool to help distinguish between the three most common causes of desquamative gingivitis.