Histology of sun-damaged human skin.

In glycomethacrylate sections of sun-exposed skin, we found the epidermis a sensitive index of damage. The stratum corneum of severely damaged skin was often compact and laminated, or gelatinous, and sometimes contained vesicles full of proteinous material. These vesicles arose from the enlarged and distinctly cellular-thick stratum lucidum. Sometimes there was no clear transition between the stratum lucidum and corneum. In the malpighian layer, cell heterogeneity, vacuolization, dysplasia, and zonal necrosis were common. The number of Langerhans cells was reduced in sun-damaged epidermis. The dermis had the usual disparate degrees of elastotic changes, with the formation of amorphous masses and the occurrence of fiber breakdown (fibrorhexis and fibrolysis). Macrophages among the elastotic masses contained coarse granules. When stained by means of the hematoxylin and Lee technique, the elastotic masses in the papillary dermis were pink or red but those in the mid dermis stained lilac to blue; all other elastic fibers stained pink or red. We found reticulin fibers predominantly around the elastotic masses and in areas of fibrorhexis and/or fibrolysis; a delicate collagenous fiber scaffolding supported the elastotic masses.