Study of hyperpigmentation in human skin disorder using different electron microscopy techniques.

There is a global trend of increase in the demand for three-dimensional electron microscopy with high resolution. The ultrastructural change and related functional studies are necessary to investigate biological phenomena. In this study, currently available 3D reconstruction techniques of electron microscopes (serial block-face scanning electron microscopy and focused ion beam-scanning electron microscopy) were used to investigate hyperpigmentary disorders in human skin. In the basal layer of the epidermis in the human skin, there are melanocytes that produce melanin and keratinocytes that act as a barrier against environmental damage. The 3D structure from serial images through scanning electron microscopy showed locations of melanosomes between melanocyte and keratinocyte in the hyperpigmentary disorder, in addition, the electron tomography showed pigment transfer through melanin instead melanosome. These results support the exocytosis-endocytosis theory of pigment in human skin.