THE EMBRYONIC-DEVELOPMENT OF MELANOCYTES AND ITS PATHOLOGY

Melanocytes of the skin do not originate from the epidermis but from a transient embryonic structure called the neural crest, which derives from the neuroectoderm. The skin pigmentation involves a set of complex developmental mecanisms occurring outside as well as inside the embryonic skin, such as the emergence of the melanocyte cell lineage among neural crest cells, the migration of melanocyte precursors from the neural primordium to the epidermis, cell proliferation and final maturation of melanoblasts into melanin producing cells. Recently published data on avian and rodent neural crest cell and melanocyte development lead to a better understanding of normal melanogenesis and of complex abnormalities of human skin pigmentation.