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.Nevus of Ota: A macular lesion on the side of the FACE, involving the CONJUNCTIVA and EYELIDS, as well as the adjacent facial skin, SCLERA; OCULOMOTOR MUSCLES; and PERIOSTEUM. Histological features vary from those of a MONGOLIAN SPOT to those of a BLUE NEVUS.Nevus, Sebaceous of Jadassohn: A syndrome characterized by lesions occurring on the face, scalp, or neck which consist of congenital hypoplastic malformations of cutaneous structures and which over time undergo verrucous hyperplasia. Additionally it is associated with neurological symptoms and skeletal, ophthalmological, urogenital, and cardiovascular abnormalities.Dysplastic Nevus Syndrome: Clinically atypical nevi (usually exceeding 5 mm in diameter and having variable pigmentation and ill defined borders) with an increased risk for development of non-familial cutaneous malignant melanoma. Biopsies show melanocytic dysplasia. Nevi are clinically and histologically identical to the precursor lesions for melanoma in the B-K mole syndrome. (Stedman, 25th ed)Nevus, Intradermal: A nevus in which nests of melanocytes are found in the dermis, but not at the epidermal-dermal junction. Benign pigmented nevi in adults are most commonly intradermal. (Stedman, 25th ed)Nevus, Epithelioid and Spindle Cell: A benign compound nevus occurring most often in children before puberty, composed of spindle and epithelioid cells located mainly in the dermis, sometimes in association with large atypical cells and multinucleate cells, and having a close histopathological resemblance to malignant melanoma. The tumor presents as a smooth to slightly scaly, round to oval, raised, firm papule or nodule, ranging in color from pink-tan to purplish red, often with surface telangiectasia. (Dorland, 27th ed)Skin Neoplasms: Tumors or cancer of the SKIN.Nevus, Halo: A benign skin lesion characterized by a zone of depigmentation surrounding the nevus.Basal Cell Nevus Syndrome: Hereditary disorder consisting of multiple basal cell carcinomas, odontogenic keratocysts, and multiple skeletal defects, e.g., frontal and temporoparietal bossing, bifurcated and splayed ribs, kyphoscoliosis, fusion of vertebrae, and cervicothoracic spina bifida. Genetic transmission is autosomal dominant.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)Facial NeoplasmsScalp: The outer covering of the calvaria. It is composed of several layers: SKIN; subcutaneous connective tissue; the occipitofrontal muscle which includes the tendinous galea aponeurotica; loose connective tissue; and the pericranium (the PERIOSTEUM of the SKULL).Dermoscopy: A noninvasive technique that enables direct microscopic examination of the surface and architecture of the SKIN.Iris Neoplasms: Tumors of the iris characterized by increased pigmentation of melanocytes. Iris nevi are composed of proliferated melanocytes and are associated with neurofibromatosis and malignant melanoma of the choroid and ciliary body. Malignant melanoma of the iris often originates from preexisting nevi.Hamartoma: A focal malformation resembling a neoplasm, composed of an overgrowth of mature cells and tissues that normally occur in the affected area.Hair Color: Color of hair or fur.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).Choroid Neoplasms: Tumors of the choroid; most common intraocular tumors are malignant melanomas of the choroid. These usually occur after puberty and increase in incidence with advancing age. Most malignant melanomas of the uveal tract develop from benign melanomas (nevi).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.Sunlight: Irradiation directly from the sun.Porokeratosis: A heritable disorder of faulty keratinization characterized by the proliferation of abnormal clones of KERATINOCYTES and lesions showing varying atrophic patches surrounded by an elevated, keratotic border. These keratotic lesions can progress to overt cutaneous neoplasm. Several clinical variants are recognized, including porokeratosis of Mibelli, linear porokeratosis, disseminated superficial actinic porokeratosis, palmoplantar porokeratosis, and punctate porokeratosis.Skin Pigmentation: Coloration of the skin.Sunburn: An injury to the skin causing erythema, tenderness, and sometimes blistering and resulting from excessive exposure to the sun. The reaction is produced by the ultraviolet radiation in sunlight.Conjunctival Neoplasms: Tumors or cancer of the CONJUNCTIVA.Eccrine Glands: Simple sweat glands that secrete sweat directly onto the SKIN.Hemangioma: A vascular anomaly due to proliferation of BLOOD VESSELS that forms a tumor-like mass. The common types involve CAPILLARIES and VEINS. It can occur anywhere in the body but is most frequently noticed in the SKIN and SUBCUTANEOUS TISSUE. (from Stedman, 27th ed, 2000)Pigmentation DisordersNeoplasms, Adnexal and Skin Appendage: Neoplasms composed of sebaceous or sweat gland tissue or tissue of other skin appendages. The concept does not refer to neoplasms located in the sebaceous or sweat glands or in the other skin appendages.Neoplasms, Multiple Primary: Two or more abnormal growths of tissue occurring simultaneously and presumed to be of separate origin. The neoplasms may be histologically the same or different, and may be found in the same or different sites.Sturge-Weber Syndrome: A non-inherited congenital condition with vascular and neurological abnormalities. It is characterized by facial vascular nevi (PORT-WINE STAIN), and capillary angiomatosis of intracranial membranes (MENINGES; CHOROID). Neurological features include EPILEPSY; cognitive deficits; GLAUCOMA; and visual defects.Eye Color: Color of the iris.Scleral Diseases: General disorders of the sclera or white of the eye. They may include anatomic, embryologic, degenerative, or pigmentation defects.Carcinoma, Basal Cell: A malignant skin neoplasm that seldom metastasizes but has potentialities for local invasion and destruction. Clinically it is divided into types: nodular, cicatricial, morphaic, and erythematoid (pagetoid). They develop on hair-bearing skin, most commonly on sun-exposed areas. Approximately 85% are found on the head and neck area and the remaining 15% on the trunk and limbs. (From DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1471)Proteus Syndrome: Hamartoneoplastic malformation syndrome of uncertain etiology characterized by partial GIGANTISM of the hands and/or feet, asymmetry of the limbs, plantar hyperplasia, hemangiomas (HEMANGIOMA), lipomas (LIPOMA), lymphangiomas (LYMPHANGIOMA), epidermal NEVI; MACROCEPHALY; cranial HYPEROSTOSIS, and long-bone overgrowth. Joseph Merrick, the so-called "elephant man", apparently suffered from Proteus syndrome and not NEUROFIBROMATOSIS, a disorder with similar characteristics.Syndrome: A characteristic symptom complex.Keratoacanthoma: A benign, non-neoplastic, usually self-limiting epithelial lesion closely resembling squamous cell carcinoma clinically and histopathologically. It occurs in solitary, multiple, and eruptive forms. The solitary and multiple forms occur on sunlight exposed areas and are identical histologically; they affect primarily white males. The eruptive form usually involves both sexes and appears as a generalized papular eruption.Skin DiseasesNevus, Spindle Cell: A form of pigmented nevus showing intense melanocytic activity around the dermo-epidermal junction. Large numbers of spindle-shaped melanocytes proliferate downward toward the dermis and usually a large amount of pigment is present. It was first described in 1976 and the bulk of patients reported have been young females with the lesions presenting on the thighs. (From Rook et al., Textbook of Dermatology, 4th ed, 1992, p185)Iris Diseases: Diseases, dysfunctions, or disorders of or located in the iris.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.Eye Neoplasms: Tumors or cancer of the EYE.ColoradoMongolian Spot: A bluish-gray to gray-brown benign, melanocytic nevus found usually in the LUMBOSACRAL REGION of dark-skinned people, especially those of East Asian ancestry. It is usually congenital or appears shortly after birth, and disappears in childhood.Leukokeratosis, Hereditary Mucosal: An autosomal dominant disorder that is manifested by thickened spongiform ORAL MUCOSA with a white opalescent tint. Other MUCOSAL TISSUE may also be involved mucosa found in the VAGINA; RECTUM, and NASAL CAVITY may be similarly involved. This form of LEUKOKERATOSIS can be caused by a mutation in the gene for KERATIN 4 and is not considered a PRENEOPLASTIC CONDITION.