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A melanocytic nevus (also known as a "Banal nevus," and "Nevocytic nevus"[1]:) is a type of lesion that contains nevus cells.[2] Some sources equate the term "mole" with "melanocytic nevus".[3] Other sources reserve the term "mole" for other purposes.[4] According to the American Academy of Dermatology, the majority of moles appear during the first two decades of a person’s life, while about one in every 100 babies is born with moles.[5] Acquired moles are a form of benign neoplasm, while congenital moles, or congenital nevi, are considered a minor malformation or hamartoma and may be at a higher risk for melanoma.[5] A mole can be either subdermal (under the skin) or a pigmented growth on the skin, formed mostly of a type of cell known as a melanocyte. The high concentration of the body’s pigmenting agent, melanin, is responsible for their dark color. Moles are a member of the family of skin lesions known as nevi.
[edit] ClassificationMelanocytic nevi represent a family of lesions. The most common variants are:
[edit] HistoryIn the 1950s and 60s (and, to lesser extent, currently) a facial mole was known as a "beauty mark" when it appeared in certain spots on a woman’s face. Examples include Marilyn Monroe, model Cindy Crawford, singer Madonna, and the fictional Ms. Pac-Man. Madonna's facial mole—below her right nostril—has been surgically removed. Almost everyone with light skin has at least one or two moles somewhere on their body, while large numbers can be concentrated on the back, chest, and arms. Darker skin shades, however, tend to have fewer moles. Some folklore about moles includes the notion that picking at a mole can cause it to become cancerous or grow back larger. While chronic picking or irritation (by clothing) of a mole can be detrimental in many ways, it has not been associated with a higher incidence of cancer.[6] But while a mole may sometimes be removed by its bearer and may not grow back larger, the resulting scar can be larger. When a mole is bothersome, physicians usually recommend that it be examined by a dermatologist to see if it should be removed. The dermatologist or plastic surgeon can perform the procedure with an eye toward preventing a larger scar. [edit] Causes and prevention[edit] GenesGenes can have an influence on a person's moles. Dysplastic nevi and atypical mole syndrome are hereditary conditions which causes a person to have a large quantity of moles (often 100 or more) with some larger than normal or atypical. This often leads to a higher risk of melanoma, a serious skin cancer.[7] Dysplastic nevi are more likely than ordinary moles to become cancerous. Dysplastic nevi are common, and many people have a few of these abnormal moles. Having more than 50 ordinary moles increases the risk of developing melanoma.[8] In the overall population, a slight majority of melanomas do not form in an existing mole, but rather create a new growth on the skin. Somewhat surprisingly, this also applies to those with dysplastic nevi. They are at a higher risk of melanoma occurring not only where there is an existing mole, but also where there are none.[9][10] Such persons need to be checked regularly for any changes in their moles and to note any new ones. [edit] SunlightUV radiation from the sun causes premature aging of the skin and skin damage that can lead to melanoma. Some scientists hypothesize that overexposure to UV, including excessive sunlight, may play a role in the formation of acquired moles.[11] However, more research is needed to determine the complex interaction between genetic makeup and overall exposure to ultraviolet light. Three strong indications that this is so (but falling short of proof), are:
Studies have found that sunburns and too much time in the sun can increase the risk factors for melanoma. This is in addition to those who have dysplastic nevi being at higher risk of this cancer. (The uncertainty is in regard to acquiring benign moles.) To prevent and reduce the risk of melanoma caused by UV radiation, the American Academy of Dermatology and the National Cancer Institute recommends staying out of the sun between 10 a.m. and 3 p.m. standard time (or whenever your shadow is shorter than your height). The National Cancer Institute also recommends wearing long sleeves and pants, hats with a wide brim, sunscreens, and sunglasses that have UV-deflecting lenses.[8] [edit] Moles and longevityMoles tend to appear during childhood and gradually disappear after middle age. People with white skin have an average of 30 moles, with some having up to 400 moles.[12] People who have moles on their skin may have a lower incidence of certain age-related diseases. The number of moles a person has correlates with telomere length, which may be of significance in the ageing process.[13] One study found that people with over 100 moles had longer telomeres than those with under 25 moles. Shorter telomeres are thought by some to be associated with a greater risk of age-related diseases.[citation needed] [edit] AppearanceAccording to the American Academy of Dermatology, the most common types of moles are skin tags, raised moles and flat moles. Benign moles are usually circular or oval and not very large, though some can be larger than the size of a typical pencil eraser. Some moles typically produce dark, coarse hair. Common mole hair removal procedures include plucking, cosmetic waxing, electrolysis, threading and cauterization. [edit] DiagnosisClinical diagnosis can be made with the naked eye using the ABCD guideline or using dermatoscopy.  [edit] Differentiation from melanomaIt often requires a dermatologist to fully evaluate moles. For instance, a small blue or bluish black spot, often called a blue nevus, is usually benign but often mistaken for melanoma.[14] Conversely, a junctional nevus, which develops at the junction of the dermis and epidermis, is potentially cancerous.[15] A basic reference chart used for consumers to spot suspicious moles is found in the mnemonic A-B-C-D, used by institutions such as the American Academy of Dermatology and the National Cancer Institute. The letters stand for Asymmetry, Border, Color, and Diameter.[5][16] Sometimes, the letter E (for Elevation or Evolving) is added. According to the American Academy of Dermatology, if a mole starts changing in size, color, shape or, especially, if the border of a mole develops ragged edges or becomes larger than a pencil eraser, it would be an appropriate time to consult with a physician. Other warning signs include a mole, even if smaller than a pencil eraser, that is different than the others and begins to crust over, bleed, itch, or becomes inflamed. The changes may indicate developing melanomas. The matter can become clinically complicated because mole removal depends on which types of cancer, if any, come into suspicion. A recent and novel method of melanoma detection is the "Ugly Duckling Sign" [17][18] It is simple, easy to teach, and highly effective in detecting melanoma. Simply, correlation of common characteristics of a person's skin lesion is made. Lesions which greatly deviate from the common characteristics are labeled as an "Ugly Duckling", and further professional exam is required. The "Little Red Riding Hood" sign, [18] suggests that individuals with fair skin and light colored hair might have difficult-to-diagnose melanomas. Extra care and caution should be rendered when examining such individuals as they might have multiple melanomas and severely dysplastic nevi. A dermatoscope must be used to detect "ugly ducklings", as many melanomas in these individuals resemble non-melanomas or are considered to be "wolves in sheep clothing"[19]. These fair skinned individuals often have lightly pigmented or amelanotic melanomas which will not present easy-to-observe color changes and variation in colors. The borders of these amelanotic melanomas are often indistinct, making visual identification without a dermatoscope very difficult. People with a personal or family history of skin cancer or of dysplastic nevus syndrome (multiple atypical moles) should see a dermatologist at least once a year to be sure they are not developing melanoma. [edit] ComplicationsExperts, such as the American Academy of Dermatology, say that vast majority of moles are benign.[5] Nonetheless, the U.S. National Cancer Institute estimated that 62,480 new cases of melanoma and 8,420 related deaths would appear in the United States in the year 2008.[20] [edit] Mole removalFirst, a diagnosis must be made. If the lesion is a seborrheic keratosis, shave excision, electrodessication or cryosurgery may be performed, usually leaving very little if any scarring. If the lesion is suspected to be a skin cancer, a skin biopsy must be done first, before considering removal. This is unless an excisional biopsy is warranted. If the lesion is a melanocytic nevus, one has to decide if it is medically indicated or not. Many insurance companies will not pay for cosmetic removal of benign moles. If a melanocytic nevus is suspected of being a melanoma, it needs to be sampled or removed and sent for microscopic evaluation by a pathologist by a method called skin biopsy. One can do a complete excisional skin biopsy or a punch skin biopsy, depending on the size and location of the original nevus. Other reasons for removal may be cosmetic, or because a raised mole interferes with daily life (e.g. shaving). Removal can be by excisional biopsy or by shaving. A shaved site leaves a red mark on the site which returns to the patient’s usual skin color in about two weeks. However, there might still be a risk of spread of the melanoma, so the methods of Melanoma diagnosis, including excisional biopsy, are still recommended even in these instances. Additionally, moles can be removed by laser, surgery or electrocautery. In properly trained hands, some medical lasers are used to remove flat moles level with the surface of the skin, as well as some raised moles. While laser treatment is commonly offered and may require several appointments, other dermatologists think lasers are not the best method for removing moles because the laser only cauterizes or, in certain cases, removes very superficial levels of skin. Moles tend to go deeper into the skin than non-invasive lasers can penetrate. After a laser treatment a scab is formed, which falls off about seven days later, in contrast to surgery, where the wound has to be sutured. A second concern about the laser treatment is that if the lesion is a melanoma, and was misdiagnosed as a benign mole, the procedure might delay diagnosis. If the mole is incompletely removed by the laser, and the pigmented lesion regrows, it might form a recurrent nevus. Electrocautery is available as an alternative to laser cautery. Electrocautery is a procedure that uses a light electrical current to burn moles, skin tags, and warts off the skin. Electric currents are set to a level such that they only reach the outermost layers of the skin, thus reducing the problem of scarring. Approximately 1-3 treatments may be needed to completely remove a mole. Typically, a local anesthetic is applied to the treated skin area before beginning the mole removal procedure.[21] For surgery, many dermatologic and plastic surgeons first use a freezing solution, usually liquid nitrogen, on a raised mole and then shave it away with a scalpel. If the surgeon opts for the shaving method, he or she usually also cauterizes the stump. Because a circle is difficult to close with stitches, the incision is usually elliptical or eye-shaped. However, freezing should not be done to a nevus suspected to be a melanoma, as the ice crystals can cause pathological changes called "freezing artifacts" which might interfere with the diagnosis of the melanoma. Electrocautery is also used for removing skin tags and only reaches the outermost level of skin so that scarring is not a problem. [edit] Superstition and ridiculeThroughout human history, individuals who have possessed facial moles have been subject to ridicule and attack based on superstition. Throughout most of history, facial moles were not considered objects of beauty on lovely faces. Rather most moles were considered hideous growths that appeared mostly on the noses, cheeks, and chins of witches, frogs and other low creatures. Both folklore and modern popular culture use physical traits to denote a character's either good or evil tendencies. In contrast to the fine features and smooth skin of its heroes and heroines, characters who possess negative or evil characteristics have also been known to possess more rugged features and skin blemishes, including facial moles. Children's stories which are high on visuals tend to paint villains as possessing such traits as facial moles. The character of Ursula, a witch from Disney's The Little Mermaid, possesses a facial mole, among other often negatively cast physical features. Ursula is contrasted with fine featured, smooth skinned Ariel.[22] Even literature that is published entirely for school-aged children, or by school-aged children, may cast villains as possessing traits such as facial moles. In 'Martha Meets Maxi', a villain is described as: A stranger with a big mole on his face broke into the taxi and drove the taxi to San Diego. The stranger's big mole is a visual representation of his state of being a villain.* [23] In Medieval Europe, among those accused of demonic possession, ecclesiastical edicts interpreted large warts and moles on the skin as physical signs of the entry point of the devil into the soul.[24] In the 16th century, a popular pseudoscience was invented that supposedly described how every facial mole had a corresponding birthmark somewhere else on the body. Once you knew where both moles were, the theory went, you had the inside track on what made the person tick. For instance, if a man had a mole on the bridge of his nose, he supposedly had another on his right thigh. Taken together, the moles meant the owners were persons of good moods and would eventually receive healthy inheritances.[25] WorldNetDaily's Maralyn Lois Polak wrote about the facial moles of U.S. Presidents. Her article spoke about personal traits that facial lesions carried. As a child, I fixated on the repugnance of warts, wens and moles, while developing a theory moles were black spots on a bad person's soul that had migrated to the surface of the skin, revealing what someone was really like.[26] [edit] See also[edit] References
[edit] External links
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