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DysplasticNevi

NATIONAL INSTITUTES OF HEALTHNational Cancer Institute

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This booklet is about certain unusualmoles called dysplastic nevi. It also tellsabout melanoma, a type of skin cancer.If you have questions, call the CancerInformation Service to learn more aboutmoles and melanoma. The staff can talkwith you in English or Spanish.

The phone number is1–800–4–CANCER(1–800–422–6237). The number fordeaf and hard of hearing callers withTTY equipment is 1–800–332–8615.The call is free.

Este folleto es acerca de ciertoslunares en la piel conocidos como“dysplastic nevi.” También nos describela melanoma, un tipo de cáncer de lapiel. Si tiene preguntas, llame al Serviciode Información sobre el Cáncer paraconocer más acerca de estos temas. Esteservicio tiene personal que hablaespañol.

El número a llamar es el 1–800–4–CANCER (1–800–422–6237).Personas con dificultades de audicióncon equipo TTY pueden llamar al1–800–332–8615. La llamada es gratis.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICESPublic Health ServiceNational Institutes of Health

Contents

Moles 2

Dysplastic Nevi 2

Melanoma 3

Prevention of Melanoma 5

Early Detection of Melanoma 6

Glossary 10

National Cancer Institute Information Resources 13

Other Booklets 15

Pictures of Ordinary Moles and Dysplastic Nevi 16

Pictures of Melanoma 18

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What You Need To Know About™ Molesand Dysplastic Nevi

he National Cancer Institute (NCI) has writtenthis booklet to help you learn more about

common moles* and unusual ones called dysplasticnevi or atypical moles. This booklet shows what moleslook like and explains how they may be related tomelanoma, a type of skin cancer. It describes the signsof melanoma and explains how you can check yourskin for moles that might be cancerous. It also explainswhy and how you can protect your skin. Other NCIbooklets about skin cancer and cancer prevention arelisted in the “Other Booklets” section.

Cancer research has led to real progress againstcancer–better survival and an improved quality of life.Through research, our knowledge about moles andcancers of the skin keeps increasing. We are findingnew ways to prevent, detect, and treat cancer. TheCancer Information Service and other sources of NCIinformation listed under “National Cancer InstituteInformation Resources” can provide the latest, mostaccurate information about moles, dysplastic nevi, andcancer. Publications mentioned in this booklet andothers are available from the Cancer InformationService at 1–800–4–CANCER. Many NCIpublications are also available on the Internet at theWeb sites listed in the “National Cancer InstituteInformation Resources” section at the end of thisbooklet.

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*Words that may be new to readers are printed in italics. Definitionsof these and other terms related to moles and melanoma are listed inthe “Glossary” section. For some words, a “sounds-like” spelling isalso given.

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Moles

oles are growths on the skin. Doctors call molesnevi (one mole is a nevus). These growths occur

when cells in the skin, called melanocytes, grow in acluster with tissue surrounding them. Moles are usuallypink, tan, brown, or flesh-colored. Melanocytes are alsospread evenly throughout the skin and produce thepigment that gives skin its natural color. When skin isexposed to the sun, melanocytes produce morepigment, causing the skin to tan, or darken.

Moles are very common. Most people have between10 and 40 moles. A person may develop new molesfrom time to time, usually until about age 40. Molescan be flat or raised. They are usually round or oval andno larger than a pencil eraser. Many moles begin as asmall, flat spot and slowly become larger in diameterand raised. Over many years, they may flatten again,become flesh-colored, and go away.

Dysplastic Nevi

bout one out of every ten people has at least oneunusual (or atypical) mole that looks different

from an ordinary mole. The medical term for theseunusual moles is dysplastic nevi. The “Pictures ofOrdinary Moles and Dysplastic Nevi” section showsthe differences between ordinary moles and dysplasticnevi.

Doctors believe that dysplastic nevi are more likelythan ordinary moles to develop into a type of skincancer called melanoma. Because of this, moles shouldbe checked regularly by a doctor or nurse specialist,especially if they look unusual; grow larger; or changein color, outline, or in any other way.

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Melanoma

elanoma is a type of skin cancer–one of the mostserious types because advanced melanomas have

the ability to spread to other parts of the body.*Melanoma begins when melanocytes (pigment cells)gradually become more abnormal and divide withoutcontrol or order. These cells can invade and destroy thenormal cells around them. The abnormal cells form agrowth of malignant tissue (a cancerous tumor) on thesurface of the skin. Melanoma can begin either in anexisting mole or as a new growth on the skin. The“Pictures of Melanoma” section shows examples ofmelanoma. A doctor or nurse specialist can tell whetheran abnormal-looking mole should be closely watchedor should be removed and checked for melanoma cells.The purpose of routine skin exams is to identify andfollow abnormal moles.

The removal of the entire mole or a sample of tissuefor examination under a microscope is called a biopsy.If possible, it is best to remove moles by an excisionalbiopsy, rather than a shave biopsy.

If the biopsy results in a diagnosis of melanoma, thepatient and the doctor should work together to maketreatment decisions. In many cases, melanoma can becured by minimal surgery if the tumor is discoveredwhen it is thin (before it has grown downward from theskin surface) and before the cancer cells have begun tospread to other places in the body. However, ifmelanoma is not found early, the cancer cells canspread through the bloodstream and lymphatic systemto form tumors in other parts of the body. Melanoma is

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*Melanoma can also develop in the eye, called intraocular melanoma,or rarely in other parts of the body where pigment cells are found.The CIS can provide information about the diagnosis and treatmentof intraocular melanoma.

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much harder to control when it has spread. The spreadof cancer is called metastasis.

Doctors and scientists believe that it is possible toprevent many melanomas and to detect most othersearly, when the disease is more likely to be cured withminimal surgery. In the past several decades, anincreasing percentage of melanomas have beendiagnosed at very early stages, when they are quite thinand unlikely to have spread. Learning about preventionand early detection, while important for everyone, isespecially important for people who have an increasedrisk for melanoma. People who are at an increased riskinclude those who have dysplastic nevi or a very largenumber of ordinary moles.

Risk Factors for Melanoma

• Family history of melanoma

• Dysplastic nevi

• History of melanoma

• Weakened immune system

• Many ordinary moles (more than 50)

• Ultraviolet (UV) radiation

• Severe, blistering sunburns

• Freckles

• Fair skin

The National Cancer Institute booklet What YouNeed To Know AboutTM Melanoma has moreinformation about risk factors for this disease.

It is important to remember that not everyone whohas dysplastic nevi or other risk factors for melanomagets the disease. In fact, most do not. Also, about halfthe people who develop melanoma do not have

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dysplastic nevi, and they may not have any otherknown risk factor for the disease. At this time, no onecan explain why one person gets melanoma whileanother does not. Research has shown that sunexposure, especially excessive exposure that leads tobad, blistering sunburns, is an important and avoidablerisk factor. Scientists are continuing their studies of riskfactors for melanoma.

Prevention of Melanoma

he number of people in the world who developmelanoma is increasing each year. In the United

States, the number has more than doubled in the past 20 years. Experts believe that much of the worldwideincrease in melanoma is related to an increase in theamount of time people spend in the sun.

Ultraviolet (UV) radiation from the sun and fromsunlamps and tanning booths damages the skin and canlead to melanoma and other types of skin cancer. (Twotypes of ultraviolet radiation–UVA and UVB–areexplained in the “Glossary” section.) Everyone,especially those who have dysplastic nevi or other riskfactors, should try to reduce the risk of developingmelanoma by protecting the skin from UV radiation.The intensity of UV radiation from the sun is greatestin the summer, particularly during midday hours. Asimple rule is to avoid the sun or protect your skinwhenever your shadow is shorter than you are.

People who work or play in the sun should wearprotective clothing, such as a hat and long sleeves.Also, lotion, cream, or gel that contains sunscreen canhelp protect the skin. Many doctors believe sunscreensmay help prevent melanoma, especially those thatreflect, absorb, and/or scatter both types of ultravioletradiation. Sunscreens are rated in strength according to

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a sun protection factor (SPF). The higher the SPF, themore sunburn protection is provided. Sunscreens withan SPF value of 2 to 11 provide minimal protectionagainst sunburns. Sunscreens with an SPF of 12 to 29provide moderate protection. Those with an SPF of 30or higher provide high protection against sunburn.Sunglasses that have UV-absorbing lenses should alsobe worn. The label should specify that the lenses blockat least 99 percent of UVA and UVB radiation.

Early Detection of Melanoma

ecause melanoma usually begins on the surface ofthe skin, it often can be detected at an early stage

with a total skin examination by a trained health careworker. Checking the skin regularly for any signs of thedisease increases the chance of finding melanoma early.A monthly skin self-exam is very important for peoplewho have any of the known risk factors, but doing skinself-exams routinely is a good idea for everyone.

Here is how to do askin self-exam:

• After a bath or shower,stand in front of a full-length mirror in a well-lighted room.Use a hand-held mirrorto look at hard-to-seeareas.

• Begin with the faceand scalp and workdownward, checkingthe head, neck,shoulders, back, chest,and so on. Be sure tocheck the front, back,

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and sides of the arms andlegs. Also, check the groin,the palms, the fingernails,the soles of the feet, thetoenails, and the areabetween the toes.

• Be sure to check the hard-to-see areas of thebody, such as the scalp andneck. A friend or relativemay be able to help inspectthese areas. Use a comb or ablow dryer to help move hairso you can see the scalp andneck better.

• Be aware of where your moles are and how theylook. By checking your skin regularly, you willbecome familiar with what your moles look like.Look for any signs of change, particularly a newblack mole or a change in outline, shape, size, color(especially a new black area), or feel of an existingmole. Also, note any new, unusual, or “ugly-looking” moles. If your doctor has taken photos ofyour skin, compare these pictures with the way yourskin looks on self-examination.

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• Check moles carefully during times of hormonechanges, such as adolescence, pregnancy, andmenopause. As hormone levels change, moles maychange.

• It may be helpful to record the dates of your skinexams and to write notes about the way your skinlooks. If you find anything unusual, see your doctorright away. Remember, the earlier a melanoma isfound, the better the chance for a cure.

In addition to doing routine skin self-exams, peopleshould have their skin checked regularly by a doctor ornurse specialist. A doctor can do a skin exam duringvisits for regular checkups. People who think they havedysplastic nevi should point them out to the doctor. It isalso important to tell the doctor about any new,changing, or “ugly-looking” moles.

Sometimes it is necessary to see a specialist. Adermatologist (skin doctor) is likely to have the mosttraining in diseases of the skin. Some plastic surgeons,general surgeons, oncologists, internists, and familydoctors also have a special interest and training inmoles and melanoma.

Melanoma may run in families, and members ofthese families are at high risk for the disease. In someof these families, certain members also have a largenumber (usually over 100) of dysplastic nevi. Thesepeople have an especially high risk of developingmelanoma. When two or more family members developmelanoma, it is important for all of the patients’ closerelatives (parents, brothers, sisters, and children abovethe age of 10) to see a doctor and be examinedcarefully for dysplastic nevi or any signs of melanoma.The doctor can then decide how often each personneeds to be seen. (Doctors may recommend that these

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family members have checkups every 6 months.)Anyone who has a large number of dysplastic nevi alsoshould be examined regularly.

A doctor may want to watch a slightly abnormalmole closely to see whether it changes over time.Pictures taken at one visit may be compared with theappearance of the mole at the next visit. Sometimes adoctor decides that a mole should be removed so thatthe tissue can be examined under a microscope. Theremoval of a mole, called a biopsy, is usually done inthe doctor’s office using local anesthetic. It generallytakes only a few minutes. The patient may requirestitches, and a small scar will remain after healing. Apathologist examines the tissue under a microscope tosee whether the melanocytes are normal, dysplastic, orcancerous.

Because most moles, including most dysplastic nevi,do not develop into melanoma, removing all of them isnot necessary. A doctor can recommend when andwhen not to remove moles. Usually, only moles thatlook like melanoma, those that change, or those that areboth new and look abnormal need to be removed.

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Glossary

Anesthetics (an-es-THET-iks): Substances that causeloss of feeling or awareness. Local anesthetics causeloss of feeling in a part of the body. General anestheticsput the person to sleep.

Biopsy (BY-ahp-see): The removal of cells or tissuesfor examination under a microscope. When only asample of the tumor is removed, the procedure is calledan incisional biopsy or core biopsy. When the wholetumor is removed, the procedure is called an excisionalbiopsy. When a sample of tissue or fluid is removedwith a needle, the procedure is called a needle biopsyor fine-needle aspiration.

Cancer: A term for diseases in which abnormal cellsdivide without control. Cancer cells can invade nearbytissues and can spread through the bloodstream andlymphatic system to other parts of the body.

Dermatologist (der-ma-TAH-lo-jist): A doctor whospecializes in the diagnosis and treatment of skinproblems.

Dysplastic nevi (dis-PLAS-tik NEE-vye): Atypicalmoles; moles whose appearance is different from thatof common moles. Dysplastic nevi are generally largerthan ordinary moles and have irregular and indistinctborders. Often their color is not uniform, and rangesfrom pink to dark brown; they usually are flat, but partsmay be raised above the skin surface.

Excisional biopsy (EX-sih-zhon-al BY-ahp-see): Thesurgical procedure of removing a tumor by cutting itout. The biopsy is then examined under a microscope.

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Familial dysplastic nevi (fa-MI-lee-yul dis-PLAS-tikNEE-vye): A condition that runs in certain families inwhich at least two members have dysplastic nevi(atypical moles) and have a tendency to developmelanoma.

Lymphatic system (lim-FAT-ik): The tissues and organsthat produce, store, and carry white blood cells thatfight infection and other diseases. This system includesthe bone marrow, spleen, thymus, and lymph nodes anda network of thin tubes that carry lymph and whiteblood cells. These tubes branch, like blood vessels, intoall the tissues of the body.

Malignant (ma-LIG-nant): Cancerous; a growth with atendency to invade and destroy nearby tissue andspread to other parts of the body.

Melanocytes (mel-AN-o-sites): Cells in the skin thatproduce and contain the pigment called melanin.

Melanoma: A form of skin cancer that arises inmelanocytes, the cells that produce pigment. Melanomausually begins in a mole.

Metastasis (meh-TAS-ta-sis): The spread of cancerfrom one part of the body to another. Cells in themetastatic (secondary) tumor are the same type as thosein the original (primary) tumor.

Mole: A benign growth on the skin (usually tan, brown,or flesh-colored) that contains a cluster of melanocytesand surrounding supportive tissue.

Nevus (NEE-vus): A benign growth on the skin, such asa mole. A mole is a cluster of melanocytes andsurrounding supportive tissue that usually appears as atan, brown, or flesh-colored spot on the skin. The pluralof nevus is nevi (NEE-vye).

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Oncologist (on-KOL-o-jist): A doctor who specializesin treating cancer.

Pathologist (pa-THOL-o-jist): A doctor who identifiesdiseases by studying cells and tissues under amicroscope.

Pigment: A substance that gives color to tissue.Pigments are responsible for the color of skin, eyes, and hair.

Risk factor: Anything that increases the chance ofdeveloping a disease.

Shave biopsy (BY-ahp-see): A procedure in which theparts of a mole that are above and just below thesurface of the skin are removed with a small blade.There is no need for stitches with this procedure.

SPF: Sun protection factor. A scale for rating the levelof sunburn protection in sunscreen products. The higherthe SPF, the more sunburn protection it provides.

Sunscreen: A substance that helps to protect the skinfrom the sun’s harmful rays. Sunscreens reflect, absorb,and/or scatter both UVA and UVB radiation. Usinglotions, creams, or gels that contain sunscreens can helpprotect the skin from premature skin aging and damagethat may lead to skin cancer.

Tumor (TOO-mer): An abnormal mass of tissue thatresults from excessive cell division. Tumors perform nouseful body function. They may either be benign (notcancerous) or malignant (cancerous).

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Ultraviolet radiation (ul-tra-VYE-o-letray-dee-AY-shun): Invisible rays that are part of theenergy that comes from the sun. UV radiation candamage the skin and cause melanoma and other typesof skin cancer. UV radiation that reaches the earth’ssurface is made up of two types of rays, called UVAand UVB rays. UVB rays are more likely than UVArays to cause sunburn, but UVA rays pass deeper intothe skin. Scientists have long thought that UVBradiation can cause melanoma and other types of skincancer. They now think that UVA radiation also mayadd to skin damage that can lead to skin cancer andcause premature skin aging. For this reason, skinspecialists recommend that people use sunscreens thatreflect, absorb, and/or scatter both kinds of UVradiation.

National Cancer Institute InformationResources

ou may want more information for yourself, yourfamily, and your doctor. The following National

Cancer Institute (NCI) services are available to helpyou.

TelephoneCancer Information Service (CIS)

Provides accurate, up-to-date information on cancerto patients and their families, health professionals, andthe general public. Information specialists translate thelatest scientific information into understandablelanguage and respond in English, Spanish, or on TTYequipment.

Toll-free: 1–800–4–CANCER (1–800–422–6237)

TTY (for deaf and hard of hearing callers):1–800–332–8615

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InternetThese Web sites may be useful:

http://www.nci.nih.gov

NCI’s primary Web site; contains information aboutthe Institute and its programs.

http://cancertrials.nci.nih.gov

cancerTrials™; NCI’s comprehensive clinical trialsinformation center for patients, health professionals,and the public. Includes information on understandingtrials, deciding whether to participate in trials, findingspecific trials, plus research news and other resources.

http://cancernet.nci.nih.gov

CancerNet™; contains material for healthprofessionals, patients, and the public, includinginformation from PDQ® about cancer treatment,screening, prevention, supportive care, and clinicaltrials; and CANCERLIT®, a bibliographic database.

E-mailCancerMail

Includes NCI information about cancer treatment,screening, prevention, and supportive care. To obtain a contents list, send e-mail tocancermail@icicc.nci.nih.gov with the word “help” inthe body of the message.

FaxCancerFax®

Includes NCI information about cancer treatment,screening, prevention, and supportive care. To obtain acontents list, dial 301–402–5874 from a fax machinehand set and follow the recorded instructions.

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Other Booklets

he National Cancer Institute booklets listed belowand others are available from the Cancer

Information Service by calling 1–800–4–CANCER.

• What You Need To Know AboutTM Cancer

• What You Need To Know AboutTM Melanoma

• What You Need To Know AboutTM Skin Cancer

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Pictures of Ordinary Moles and Dysplastic Nevi

Ordinary Moles

Evenly tan or brown; all typicalmoles on one person tend to looksimilar.

Round or oval, with a distinctedge that separates the mole fromthe rest of the skin.

Begin as flat, smooth spots onskin (1a); may become raised (1b)and form a smooth bump (1c).

Usually less than 5 millimeters(about 1/4 inch) across (size of apencil eraser).

Between 10 and 40 typical molesmay be present on an adult’sbody.

Usually found above the waist onsun-exposed surfaces of the body.Scalp, breasts, and buttocks rarelyhave normal moles.

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Dysplastic Nevi

Mixture of tan, brown, andred/pink. A person’s moles oftenlook quite different from oneanother.

Have irregular, sometimesnotched edges. May fade intothe skin around it. The flatportion of the mole may be levelwith the skin.

May have a smooth, slightlyscaly, or rough, irregular,“pebbly” appearance.

Often larger than 5 millimeters(about 1/4 inch) across and sometimes larger than 10 millimeters (about 1/2 inch).

May be present in large numbers(more than 100 on the sameperson). However, some peoplehave only a few dysplastic nevi.

May occur anywhere on thebody but most frequently on theback and areas exposed to thesun. May also appear below thewaist and on the scalp, breasts,and buttocks.

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Pictures of Melanoma

Large size Most melanomas are at least 5 millimeters(about 1/4 inch) across when they are found;many are much larger. An unusually largemole may be melanoma.

Many colors A mixture of tan, brown, white, pink, red, gray,blue, and especially black in a mole suggestsmelanoma.

Irregular border If a mole has an edge that is irregular ornotched, it may be melanoma.

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Abnormal surface If a mole is scaly, flaky, oozing, or bleeding, hasan open sore that does not heal, or has a hardlump in it, it may be melanoma.

Unusual sensation If a mole itches or is painful or tender,melanoma may be present.

Abnormal skin If color from the mole spreads into the around mole skin around it or if this skin becomes red

or loses its color (becomes white or gray), melanoma may be present.

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The National Cancer Act, passed by Congress in1971, made research a national priority. Since that time,the National Cancer Institute (NCI), the lead Federalagency for cancer research, has collaborated with topresearchers and facilities across the country to conductinnovative research leading to progress in cancerprevention, detection, diagnosis, and treatment. Theseefforts have resulted in a decrease in the overall cancerdeath rate, and have helped improve and extend thelives of millions of Americans.

National Cancer Institute materials and artwork arein the public domain and not subject to copyrightrestrictions when they are produced by Governmentemployees. However, most NCI materials aredeveloped by private sector writers, designers,photographers, and illustrators under contract to theGovernment. The copyright for these materials oftenremains in the hands of the originators, and it isnecessary to request permission to use or reproducethese materials. In many cases, permission will begranted, although a credit line and/or fees for usagemay be required. To obtain permission, write toPermissions Department, National Cancer Institute,Room 10A28, 31 Center Drive, MSC 2580, Bethesda,MD 20892–2580.

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NIH Publication No. 99–3133Revised June 1999

Printed September 1999P028

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