ELECTRON MICROSCOPY OF MELANOCYTES AND LANGERHANS CELLS IN HUMAN FETAL EPIDERMIS AT 14 WEEKS

[摘要] Epidermal melanocytes containing non-melanized premelanosomes were present in the basal and lower intermediate layers of the epidermis. No melanocytes were seen in the dermis, and cells in this situation, which may have been melanoblasts, could not certainly be classed as such in the absence of positive criteria for identification. The very few Langerhans cells present were practically identical in appearance with those of adult epidermis, and none contained premelanosomes in the cytoplasm. The observations definitely indicate that the Langerhans cell is not the outworn remnant of a previously melanogenic melanocyte. The bearing of the results on other views concerning the nature of this cell is discussed.