Lentigo: Small circumscribed melanoses resembling, but differing histologically from, freckles. The concept includes senile lentigo ('liver spots') and nevoid lentigo (nevus spilus, lentigo simplex) and may also occur in association with multiple congenital defects or congenital syndromes (e.g., Peutz-Jeghers syndrome).Hutchinson's Melanotic Freckle: A cellular subtype of malignant melanoma. It is a pigmented lesion composed of melanocytes occurring on sun-exposed skin, usually the face and neck. The melanocytes are commonly multinucleated with a "starburst" appearance. It is considered by many to be the in situ phase of lentigo maligna melanoma.Hyperpigmentation: Excessive pigmentation of the skin, usually as a result of increased epidermal or dermal melanin pigmentation, hypermelanosis. Hyperpigmentation can be localized or generalized. The condition may arise from exposure to light, chemicals or other substances, or from a primary metabolic imbalance.LEOPARD Syndrome: An autosomal dominant disorder with an acronym of its seven features (LENTIGO; ELECTROCARDIOGRAM abnormalities; ocular HYPERTELORISM; PULMONARY STENOSIS; abnormal genitalia; retardation of growth; and DEAFNESS or SENSORINEURAL HEARING LOSS). This syndrome is caused by mutations of PTPN11 gene encoding the non-receptor PROTEIN TYROSINE PHOSPHATASE, type 11, and is an allelic to NOONAN SYNDROME. Features of LEOPARD syndrome overlap with those of NEUROFIBROMATOSIS 1 which is caused by mutations in the NEUROFIBROMATOSIS 1 GENES.Facial NeoplasmsMelanosis: Disorders of increased melanin pigmentation that develop without preceding inflammatory disease.Skin Neoplasms: Tumors or cancer of the SKIN.Cafe-au-Lait Spots: Light brown pigmented macules associated with NEUROFIBROMATOSIS and Albright's syndrome (see FIBROUS DYSPLASIA, POLYOSTOTIC).Nevus: A circumscribed stable malformation of the skin and occasionally of the oral mucosa, which is not due to external causes and therefore presumed to be of hereditary origin.Palatal Neoplasms: Tumors or cancer of the PALATE, including those of the hard palate, soft palate and UVULA.Hypopigmentation: A condition caused by a deficiency or a loss of melanin pigmentation in the epidermis, also known as hypomelanosis. Hypopigmentation can be localized or generalized, and may result from genetic defects, trauma, inflammation, or infections.Noonan Syndrome: A genetically heterogeneous, multifaceted disorder characterized by short stature, webbed neck, ptosis, skeletal malformations, hypertelorism, hormonal imbalance, CRYPTORCHIDISM, multiple cardiac abnormalities (most commonly including PULMONARY VALVE STENOSIS), and some degree of INTELLECTUAL DISABILITY. The phenotype bears similarities to that of TURNER SYNDROME that occurs only in females and has its basis in a 45, X karyotype abnormality. Noonan syndrome occurs in both males and females with a normal karyotype (46,XX and 46,XY). Mutations in a several genes (PTPN11, KRAS, SOS1, NF1 and RAF1) have been associated the the NS phenotype. Mutations in PTPN11 are the most common. LEOPARD SYNDROME, a disorder that has clinical features overlapping those of Noonan Syndrome, is also due to mutations in PTPN11. In addition, there is overlap with the syndrome called neurofibromatosis-Noonan syndrome due to mutations in NF1.Dermoscopy: A noninvasive technique that enables direct microscopic examination of the surface and architecture of the SKIN.Nevus, Pigmented: A nevus containing melanin. The term is usually restricted to nevocytic nevi (round or oval collections of melanin-containing nevus cells occurring at the dermoepidermal junction of the skin or in the dermis proper) or moles, but may be applied to other pigmented nevi.Skin Pigmentation: Coloration of the skin.Melanoma: A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)Sunlight: Irradiation directly from the sun.