PIGMENT ACTIVITY IN DERMAL NEVI INDUCED BY ULTRAVIOLET LIGHT - AN ENZYME HISTOCHEMICAL STUDY

[摘要] Ultraviolet light irradiation of flesh-colored dermal nevi has been shown to induce pigment activity in the surface cells of the dermal nevus. Cholinesterase was present in the deeper cells of the dermal nevus, and both cholinesterase and tyrosinase appeared in the middle dermal nevus cells. This experiment explains why dermal nevi will often have a pigmented cap despite the lack of junctional activity. The co-existence of these two enzymes in the dermal nevus implies a common cell of origin from the neural crest.