[Ultrastructural changes in the epidermis in ichthyosis vulgaris]

Electron-microscopic examinations of the epidermis in 11 patients suffering from xeroderma with autosomal dominant and X-recessive inheritance have revealed changes in the basal membrane, scarce pinocytotic vesicles near the basal membrane, inter- and intracellular edemas in the epidermis, a decrease of the desmosomal contacts and an increased number of microvilli on the epidermocytes of the basal and prickle-cell layers, condensation of the nucleoplasm, reduced counts of organelles and condensation of the epidermocyte tonofilaments, hyperkeratosis, and an elevated count of the desmosomes in the horny layer in both forms of ichthyosis. Autosomal dominant ichthyosis is characterized by the presence of just few intact, or by complete absence of keratohyalin granules in the granular layer. The detected ultrastructural signs may be used in the differential diagnosis between various ichthyosis forms and may contribute to deciphering the pathogenetic mechanisms of impairment of keratinization in this hereditary dermatosis.