Ultrastructure of Senile Keratosis

Abstract

Three cases of a hypertrophic type of senile keratosis were examined by an electron microscope. All three showed similar changes, although some variability from case to case was also observed. Lesional epidermis showed widened intercellular spaces with microvilli‐formation, a general increase in the bulk of the basal cells, a decrease in number of desmosomes, a decrease in the amount of tonofilaments, various degrees of aggregations of tonofibrils, binucleated keratinocytes, mitotic figures, prominent nucleoli, and an increase in number of nuclear bodies. In lesional dermoepidermal junctions, discontinuity of the basal lamina with cytoplasmic projections of the basal cells to the upper dermis was not infrequently observed. These changes are similar to those found in Bowen's disease, but are somewhat milder. In addition, in one case, keratinocytes of lesional epidermis showed lamellar structures closely associated with the rough endoplasmic reticulum. Significance of these structures is discussed.

Ultrastructure of an Atrophic Type of Senile Keratosis

“…Senile keratosis (SK) has been classified as one of the premalignant epidermal tumors usually arising on sun -exposed areas of the aged. Although there have been comprehensive descriptions from the clinico-histopathological standpoint (1)(2)(3)(4)(5)and SK is not infrequently encountered, no ultrastructural studies of SK have been reported to date except for one (6) on a hypertrophic type of SK. In the present study, three cases of SK, all of which were histologically atrophic, were examined by electron microscopy.…”

“…In the present study, three cases of SK, all of which were histologically atrophic, were examined by electron microscopy. The ultrastructural findings were compared with those from a hypertrophic type of SK (6) and from Bowen's disease (7 -10).…”