Immunomorphological features of lichen sclerosus in initial and late stages

Introduction. Lichen sclerosus is a chronic inflammatory disease of the skin and mucous membranes, combining degenerative changes in the epidermis and dermis. Histological examination is needed due to diverse nosologies with similar clinical manifestations. Early development stages of lichen sclerosus are characterized by nonspecific histological changes. However, some changes can serve as indicators for accurate diagnosis. Materials and methods. The diagnosis was confirmed by typical clinical manifestations, medical history, and laboratory abnormalities. Biopsy samples were taken from early-stage lesions and recent rash sites. The patients were divided into two groups: group 1 consisted of patients with clinical manifestations of the disease lasting less than one year and group 2 included the patients who had symptoms for more than two years. Serial paraffin sections were stained with hematoxylin and eosin as well as Van Gieson’s picric fuchsin. We performed immunohistochemical analysis using polyclonal antibodies against CD95 and monoclonal antibodies against CD31. We evaluated the findings of the immunohistochemical assay semi-quantitatively in each case for every marker. Morphometric analysis of microvessels was conducted, and the expression intensity was determined. Results. We identified new extended criteria for the differential diagnosis of lichen sclerosus including the disease duration (the presence and prevalence of rashes, erosions, presence or absence of cracks), evaluation of the microcirculatory involvement, determination of the percentage of vascular damage, and the assessment of the severity of endothelial changes. Conclusion. By means of morphological analysis, we determined the diagnostic criteria for early and late stages of lichen sclerosus. Our research results and literature data analysis showed that damaged vascular wall was the main and determining factor of lichen sclerosus pathogenesis. Keywords: lichen sclerosus, histological analysis, immunohistochemical analysis, diagnostic criteria, vascular damage