[Seborrheic keratoses studied using scanning electron microscopy].

Ten seborrheic keratosis of acanthotic type have been observed by S.E.M. The morphological study could confirm the existence of two processes in the origin of the horny cysts which are peculiar to this affection. a) an extrafollicular process causes the involvement of groups of keratinocytes which, by assuming a vortex disposition, produce a concentric keratinization; b) a follicular process which causes an accentuated keratinization of the cells surrounding the epithelial sheath. This process was associated to the presence of multiple hairs a single follicle. Moreover, with higher magnification, it was possible to observe a great number of bacteria, yeasts and of particular alteration of the membrane which could be compared to changes in the tone filaments.