Many different diseases can cause melanin pigmented lesions in the mouth through # Increase in the number of melanocytes or melanocytosis # Increased melanin production with or without melanocytosis Melanin is an endogenous pigment synthesized by melanocytes that are located in the basal layer of epithelium. Melanin is then transferred to keratinocytes in melanosomes. Nevus cells in the skin and<unk>  mucosa also produce melanin.<unk>  melanosis can present as black, gray, blue or brown lesions depending on the site and amount of melanin deposition in tissues. Physiological Increased melanin production without increase in melanocytes Peutz-Jeghers syndrome Increased production of melanin without increase in number of melanocytes Addison’s disease Decrease in blood adrenocortical hormone level causes increased levels of adrenocorticotropic hormone secreted by anterior pituitary gland. As a result, melanocyte-stimulating hormone is induced which causes<unk>  melanosis Smoker’s melanosis Increased melanin production to defend against damage from tobacco smoke<unk>  melanoacanthoma Increased number of dendritic melanocytes Melanocytic nevi Accumulation of nevus cells at the basal layer of the epithelium or in the connective tissue or both<unk>  melanoma Increased number of malignant melanocytes
Oral pigmentation
Nipple pigmentation
Breast hypertrophy
Hypopigmentation
Trichomegaly
Blue nails
Tooth discoloration
Green nails