الفهرس 
Melanocytes Biology
Agouti signaling proteinOnly 14 pages are availabe for public view
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Abstract
Melasma is a common acquired disorder of hyperpigmentation appearing on sun exposed areas especially on the forehead, malar areas upper lip and chin as macules and patches varying in color from light brown to black. Many factors have been incriminated in the etiology of melasma as genetic predisposition, pregnancy, oral contraceptive pills and sun exposure Diagnosis of melasma depends mainly on determination of melanin location in different layers of the skin which is important before deciding the treatment strategy Histopathology is a method of diagnosis of melasma, many different stains and markers used for determining the location of melanin as H&E Fontana-Masson stain and immunohistochemical stain with HMB-45 Dermoscopy is a non invasive, simple, and cheap diagnostic technique that permits the visualization of specific features of melasma that are not visible to the naked eye. Use of dermoscopy in diagnosis of melasma shows pigment network differs in colour from brown to blue gray. The colour of the pigment network indicates the location of melanin in different layers of the skin.