Mucosal lichen sclerosus/lichen planus overlap syndromes

Summary Lichen sclerosus and lichen planus affecting cutaneous sites are easily distinguishable clinically. Clinical signs on mucosal sites, however, may not allow differentiation between these diseases, and reliance is frequently placed on histopathological findings. We report a series of seven patients with clinical evidence of coexisting vulval lichen sclerosus and lichenoid oral lesions. All patients had vulval biopsies, and four had oral biopsies. Histology of all the vulval biopsy specimens showed features consistent with lichen sclerosus. Two of these patients developed vulval intraepithelial neoplasia during the course of their disease, and one progressed to a well-differentiated squamous carcinoma. Histology of the oral lesions showed features that were predominantly those of lichen planus. There are, however, few reports of histologically proven oral lichen sclerosus. Variations in histopathological descriptions of lichen sclerosus, depending on duration of disease, have been reported, particularly with regard to the position of the inflammatory infiltrate in relation to the dermo-epidermal junction. We believe that these patients may have oral lichen sclerosus, or at the very least make up a distinctive group who need to be identified and followed up, as their risk of oral dysplasia is unknown.