Stem Cells for Epidermal Melanocytes-A Challenge for Students of Dermatopathology

Many obstacles to belief in stein cells for melanocytes arise in the routine practice Of Cutaneous histopathology. However, the fundamental principle of stein cell theory says that normal stein cells arise during development, are present in adult organs as tissue-determined stern cells, and are little changed, if at all, from their embryonic counterparts. This paradox can be resolved by focusing Oil the process of epidermal melanocyte development in utero. Stein cells for melanocytes originate in the neural crest. Although much remains to be learned, this author proposes that these stem cells then take a small step to the paraspinal ganglia and then follow the axonal signposts to the skin provided in the course of normal cutaneous innervation. The epidermis may then induce these stein cells in the nerve sheath to give rise to immature dermal melanocytes, which migrate up into the epidermis. It is proposed that these melanocyte stein cells also persist after birth in the superficial nerve sheath and give rise to transient, miniature, inconspicuous dermal migratory melanocytes when replacements for epidermal melanocytes are needed in postnatal skin.