The Physiology of Pigmented Nevi

摘要: Melanocytes are pigment-producing cells derived from the neural crest. These specialized exocrine produce melanin, which is packaged and dispersed to neighboring keratinocytes in organelles called melanosomes. Within melanocyte, tyrosine converted dopa, then dopaquinone via bifunctional enzyme tyrosinase. Dopaquinone oxidized further form pigment melanin. Each epidermal melanocyte secretes melanosomes approximately 36 adjacent keratinocytes, forming an melanin unit. Genetically programmed constitutive skin color determined by amount of cutaneous pigmentation. The common mole or acquired melanocytic nevus (AMN) a collection nevomelanocytes grouped into nests located epidermis (junctional nevus), dermis (dermal both (compound nevus). It hypothesized that either melanoblasts dermal Schwann cells. AMN first appear at 1 year age, peaking number during second third decades life, disappearing seventh ninth decades. may suddenly become more prominent response sun exposure, cortisone corticotropin, blistering diseases, chemotherapy, immunosuppression, other factors not well-defined. Reports increasing size darkening puberty pregnancy have been reported but quantitated systematically.melanocytes, nevi.