Histopathological and ultrastructural studies of lichen sclerosus et atrophicus of the vulva

Histopathological and ultrastructural studies of 82 skin specimen from 81 cases of Lichen sclerosus et atrophicus (LSA) are reported. Among 64 cases of fully developed LSA, 65 specimens showed atrophy of the epidermis and hydropic degeneration at the basal layer. The collagenous fibers were swollen and homogeneous n the superficial dermis with inflammatory cells infiltrating beneath the areas of collagenous homogenization. There were 4 early cases of LSA in which epithelial thinning with flattening of the rete ridges, lichenoid lymphocytes and some histiocytes in the papillary dermis and along the dermo-epidermal junction were seen. Lichen simplex chronicus superimposed upon LSA lesions was present in 13 cases showing hyperplastic epidermis, all other observations were the same as those described in fully developed LSA. By electron microscopy, the intercellular spaces in the lesions appeared dilated, particularly those near basal cells, and desmosomes were found to be fewer than normal. Some lymphocytes and neutrophilic granulocytes were seen in the epithelial basement membrane, which was thinner than that in normal samples. Collagen fibers of varying diameters were arranged irregularly and with unclear fine structures.