ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Nevus

Updated on March 23, 2012
Source

A nevus is a a birthmark or mole. In broad usage, a nevus (or naevus) is any nonmalignant mark, spot, or growth in the skin believed to be of essentially congenital or developmental origin. In more restricted usage, a nevus is a lesion that primarily contains an accumulation of cells derived from the embryonic neural crest- namely, melanocytes (melanin-pigment-forming cells) and nevus cells or from nevus cells alone, as is the case in common brown hairy moles. The relative number of nevus cells and melanocytes in common pigmented or papular moles is widely variable. The greater the number of melanocytes, the darker brown is the color of the lesion. Where the melanocytes are deeply situated below the skin surface, the lesions assume a dark bluish hue.

Caucasian adults have an average of about 20 pigmented nevi on the skin, with wide individual variations both in the size and number of such lesions. Although the great majority of pigmented nevi are less than 1 cm in diameter, on very rare occasions large areas of the skin surface may be entirely covered by such lesions. Less than 13 of pigmented nevi are evident at birth. The great majority appear during childhood and early adult life, often as tiny frecklelike spots that grow to little dome-shaped elevations. Malignant neoplasms arise scarcely more frequently from small common pigmented nevi than from equivalent areas of normal skin.

Vascular nevi, or birthmarks, are maldevelop-ments of vascular elements in the skin. They consist mostly of richly anastomosing, variably-sized and shaped conglomerations of oversized capillary, venous, or lymphatic channels. Such maldevelopments are known as angiomas, and angiomas consisting mostly of blood vessels are known as hemangiomas. The common, elevated, strawberry type of superficial hemangioma that appears and grows only during the first few months of infancy often shrinks spontaneously. Angiomatous nevi acquired in adult life, nonpal-pable so-called port-wine stains, and deeply situated spongy or cavernous angiomas are generally permanent.

Various epidermal and connective-tissue elements of the skin may also show benign, basically congenital overgrowth or maldevelopment to give rise to a great variety of persistent wartlike or other disfiguring marks on the skin. Occasionally, epidermal nevi are displayed in bizarre linear distribution patterns.

Comments

    0 of 8192 characters used
    Post Comment

    No comments yet.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)