[Keratinization of the senile epidermis (author's transl)]

The ultrastructural study of the senile epidermis without an apparent lesion, in the phase of cicatrization of a traumatic lesion and in a state of hyperkeratosic transformation in comparison with those performed in the normal epidermis, reveals decrease in the number of clear keratinocytes (only compensated in the process of cicatrization) it is in concord with the most recent theory of the aging of cells of Gelfant and Smith. The increase of clear suprabasal cells in the epidermis degenerative process with a constant of the percentage of clear and dark basal cells suggest a liberation of bloqued cells, which constituted probably the direct source of neoplasic differentiation.