[Electron microscopic observations in leukoedema exfoliativum mucosae oris (white sponge nevus)]

Biopsia taken from 13 cases of leukoderma exfoliativum mucosae oris (white sponge nevus) was investigated by the aid of electron microscope. Significant changes as compaired to the normal ultrastructure were revealed. The disease is a hereditary one manifesting itself in the disturbance of differentiation of epithelial cells mainly of the oral mucosa. Arrangment of the tonofilaments is disturbed, formation of tonofibrills and keratohyaline granules ceases. Odland-bodies occure in a great number but the lack of emptiing their content into the interecellular space is striking. Exfoliation of the epithelial cells diminishes, presumably because of the disturbance of their enzymatic function and the presence of a great number of desmosomes between the cells of the superficial layer. The diminished exfoliation histologically and clinically produces a hyerplasia of the epithelium with an enormous quantitity of superficial epithelial cells.