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Melanoma Explained

How Do I Know If It's Melanoma?

The ABCDEFG rules are a handy guide when check­ing for signs of melanoma. In this fea­ture, we’ll cov­er each of these rules, start­ing with the let­ter ​‘A’ for Asym­me­try.
A person holds a camera displaying an image of another individual, symbolising awareness of melanoma detection
MoleMap Team
January 19, 2024

These guide­lines are endorsed by many non-prof­it skin can­cer author­i­ties around the world, includ­ing Melanoma New Zealand. When check­ing your skin, or the skin of your loved ones, look out for the following:

A is for Asym­me­try

A is for Asym­me­try

So what does ​‘asym­me­try’ mean, and what does it look like?

An asym­met­ric mole is one that’s irreg­u­lar-shaped, uneven or lop-sided — you can try draw­ing an imag­i­nary line in any direc­tion through the mid­dle of a mole and then look for moles where one half does not match the other.

In gen­er­al, nor­mal moles are even­ly-coloured in brown, tan or black, and either flat or raised on the skin. They’re usu­al­ly fair­ly sym­met­ri­cal too.

nor­mal moles are often oval-shaped
Image: nor­mal moles are often oval-shaped, even­ly coloured, and cre­ate either raised or flat sur­faces on the skin

If you notice any mole on your skin that is irreg­u­lar in shape, it would pay to get it checked — it could be an ear­ly warn­ing sign of melanoma.

der­mato­scopes
Image: to an untrained eye, melanoma can look much like any oth­er spot.

At MoleMap, our Melanog­ra­phers use spe­cial ​‘der­mato­scopes’ and oth­er high res­o­lu­tion imag­ing equip­ment to look deep inside a mole’s struc­ture. For medi­um-to-high risk patients, our skin-map­ping tech­nol­o­gy is used to track changes over time.

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B is for Bor­ders In nor­mal moles,

B is for Bor­ders
B is for Bor­ders

B is for Bor­ders In nor­mal moles, the bor­ders or ​‘edges’ of are fair­ly round and even­ly formed. If you notice that the edges are becom­ing ragged, vary from sharp to fuzzy, or are notched, scal­loped or blurred — get a pro­fes­sion­al skin check straight away.

In nor­mal moles, the bor­ders or ​‘edges’ of are fair­ly round and even­ly formed. If you notice that the edges are becom­ing ragged, vary from sharp to fuzzy, or are notched, scal­loped or blurred — get a pro­fes­sion­al skin check straight away.

moles with unusu­al bor­ders were diag­nosed as melanoma
Image: these moles with unusu­al bor­ders were diag­nosed as melanoma

Also, the pig­ment might start to spread into the skin out­side the mole — that’s not so nor­mal! It could be an ear­ly warn­ing sign of melanoma, so it’s a good idea to get it checked as soon as possible.

C is for Colour

C is for Colour

C is for Colour

Moles can be all sorts of dif­fer­ent colours – that’s quite nor­mal. Most com­mon­ly, they’re an even­ly coloured spot on the skin, either flat or raised, round or oval. They can be flesh coloured, tan, brown or even black – and they can also dark­en over time or from expo­sure to the sun.

moles with unusu­al colour­ing were diag­nosed as melanoma
Image: these moles with unusu­al colour­ing were diag­nosed as melanoma

Once a mole has devel­oped, it will usu­al­ly stay the same size, shape, and col­or for many years. How­ev­er … if a mole is chang­ing in colour rapid­ly or sud­den­ly, is uneven in colour and/​or has mul­ti­ple colours in it (includ­ing dif­fer­ing shades of brown, tan or black, or patch­es of pink, red, white or blue) it may be of con­cern and you should get it checked out straight away.

You should also watch out for:

  • Moles that are large and brown­ish with dark­en­ing speckles.
  • The pig­ment of a mole or spot that’s spread­ing from the bor­der into sur­round­ing skin — see ​‘B’ is for Bor­ders above.
  • Spots under fin­ger­nails or toe­nails that are chang­ing in colour – or a dark stripe run­ning through a fin­ger­nail or toe­nail (that’s not caused by trau­ma to your nail).

If you have any of the above symp­toms, it doesn’t mean they are melanoma, but it would pay to have them checked by skin can­cer detec­tion experts as soon as pos­si­ble to make sure.

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Which skin colour is most at risk of skin can­cer?

As most of us know, peo­ple with fair or very pale skin (par­tic­u­lar­ly those who have a lot of moles and freck­les), are most at risk of skin can­cer. If you have olive or dark skin, your risk is reduced – but remem­ber that low risk doesn’t mean NO risk. Peo­ple with dark­er skin can still get melanoma – in fact, the famous Jamaican musi­cian Bob Mar­ley died as a result of an untreat­ed melanoma on his toenail!

What’s more, dark­er skinned peo­ple often aren’t as vig­i­lant about wear­ing sun­screen and oth­er sun safe­ty pre­cau­tions as those with paler, freck­li­er skins, so their skin can end up with a lot more harm­ful sun dam­age over time.

D is for Diameter
D is for Diameter

When it comes to moles and oth­er spots, size does mat­ter – espe­cial­ly a change in size. The gen­er­al rule is that if a mole is big­ger than 6mm (i.e. the size of a pea or the eras­er on a pen­cil), it can be a warn­ing sign of melanoma. The ear­li­er melanoma is detect­ed, the bet­ter, so don’t wait for a sus­pi­cious-look­ing mole to grow to 6mm in size.

Dan­ger­ous moles com­mon­ly tend become big­ger in size over weeks or months – although con­verse­ly, they can become small­er as well. Both changes are a cause for con­cern. One impor­tant thing to note is that dan­ger­ous moles also tend to grow uneven­ly and have ragged or uneven borders.

D also stands for ​‘dark’. No mat­ter what the size of a spot, if it’s dark — or grow­ing dark­er — it can be sign of melanoma. A tiny but very dark spot can be very dan­ger­ous, so if you notice a spot like this, it’s impor­tant to get it checked out as soon as possible

6mm and diag­nosed as melanoma
Image: these moles were larg­er than 6mm and diag­nosed as melanoma.

I have a large mole – does it mean it’s melanoma?

Lots of peo­ple (espe­cial­ly old­er peo­ple) have large ​‘sun spots’ (solar lentig­ines) on parts of their body that have been exposed to the sun. Sun spots, also known as ​‘age spots’ or ​‘liv­er spots’, are not nec­es­sar­i­ly dan­ger­ous in them­selves, but they can be a warn­ing sign that you’ve had too much sun expo­sure and there­fore have a high­er risk of melanoma.

sunspots
Image: sunspots are often a sign of over­ex­po­sure to the sun

What about sun spots – are they dangerous?

Lots of peo­ple (espe­cial­ly old­er peo­ple) have large ​‘sun spots’ (solar lentig­ines) on parts of their body that have been exposed to the sun. Sun spots, also known as ​‘age spots’ or ​‘liv­er spots’, are not nec­es­sar­i­ly dan­ger­ous in them­selves, but they can be a warn­ing sign that you’ve had too much sun expo­sure and there­fore have a high­er risk of melanoma.

E is for Evolv­ing
E is for Evolv­ing (or Ele­vat­ed)

As we age, our skin is con­stant­ly chang­ing. It’s all just a nor­mal part of get­ting old­er, but, when it comes to moles and oth­er spots, change isn’t always a good thing.

Moles usu­al­ly emerge in child­hood and ado­les­cence, and change in size and colour as you grow. New moles can also appear at times when your hor­mone lev­els change, such as dur­ing preg­nan­cy. They can appear any­where on your body, alone or in groups.

The appear­ance of a new mole or spot, or a change in an exist­ing freck­le or mole, can be an ear­ly sign of a melanoma.1 The change may be in asym­me­try, bor­ders, colour or size (see A,B,C,D above) and nor­mal­ly occurs over sev­er­al weeks or months. Oth­er changes to watch for include itch­ing, bleed­ing, ooz­ing or crust­ing – these are the most con­cern­ing of all the melanoma warn­ing signs.2

melanoma devel­op­ing in between skin checks
Image: this ​‘before and after’ image shows melanoma devel­op­ing in between skin checks — this illus­trates the ben­e­fit of a skin-map­ping ser­vice like a Full Body MoleMap, which tracks changes to your skin over time

Should I be wor­ried if a mole is elevated?

There are many rea­sons why moles can be raised. The main one is that it’s a healthy, benign mole (usu­al­ly genet­ic) mole that you’ve had for a while and feels soft and some­times wob­bly to touch. These benign moles can lose colour or get dark­er with age and should be mon­i­tored for any dras­tic change, but gen­er­al­ly aren’t cause for concern.

How­ev­er, moles that change and become raised could be an indi­ca­tion of melanoma — in this case, we rec­om­mend seek­ing advice from skin can­cer detec­tion specialists.

F is for Firm
F is for Firm

Nodu­lar melanoma accounts for about 15% of melanoma in Aus­tralia and New Zealand5. This type of melanoma can affect any­one, but is gen­er­al­ly much more com­mon in men over 50 and those with fair skin6.

The fright­en­ing thing about nodu­lar melanoma is that because it grows fast, it can pen­e­trate deep with­in the skin very quick­ly (with­in a few months of appear­ance), which is why it’s so dan­ger­ous and needs ear­ly diag­no­sis and removal.

Image: exam­ples of nodu­lar melanoma
Image: exam­ples of nodu­lar melanoma

What are the ear­ly signs of nodu­lar melanoma?

Nodu­lar melanoma usu­al­ly presents as a rapid­ly enlarg­ing lump (over sev­er­al weeks to months). It may arise as a new lump or with­in an exist­ing mole any­where on the body, although it’s most com­mon­ly found on exposed areas of the head and neck.

Nodu­lar melanoma isn’t nec­es­sar­i­ly dark or coloured, but the key give­away is that it’s raised, often sym­met­ri­cal, firm to touch, and is chang­ing or grow­ing. In the ear­ly stages, this change might just be a sense of change rather than vis­i­ble – per­haps the mole is itchy, or just feels fun­ny. The signs of nodu­lar melanoma include:

  • A dome-shaped, firm, often sym­met­ri­cal lump
  • Larg­er size than most moles – more than 6mm and often 10mm or more in diam­e­ter at diagnosis
  • May be a sin­gle colour or vari­able colours – most often black, red or skin coloured
  • Smooth, rough, crust­ed or warty surface
  • Ulcer­a­tion or bleeding
  • Itch­ing or stinging

How can you tell if a mole is firmer than usual?

Nor­mal (benign) moles are usu­al­ly soft to the touch. They might feel ​‘spongy’ or ​‘wob­bly’ when you press on them. But if a mole feels firm, scaly or rough – or if you can feel a hard lump – it can be a cause for con­cern. What’s more, a lump doesn’t have to be big for the growth to be dangerous.

If you notice any unusu­al mole or lump that feels firm, or has any of the above fea­tures, we rec­om­mend hav­ing a Skin Check or Full Body MoleMap as soon as possible.

G is for Growing
G is for Growing

Melanoma is, by def­i­n­i­tion, a muta­tion of cells, which means that they grow out of con­trol. So one of the best ways to spot the ear­ly signs of melanoma or oth­er skin can­cers is to look for a mole that’s grow­ing or chang­ing — espe­cial­ly one that’s grow­ing rapidly.

If that growth is com­bined with E (ele­vat­ed) and F (firm to the touch), that’s even more rea­son to get your skin checked – and straight away – as it may be a sign of nodu­lar melanoma, one of the most dan­ger­ous, fastest-grow­ing forms of melanoma (see ​‘E’ and ​‘F’ above).

Should you be wor­ried about a grow­ing mole?

Short answer, yes. If you’ve noticed a grow­ing or chang­ing mole or spot on your skin (or on some­one else’s skin), always get it pro­fes­sion­al­ly checked by a skin can­cer detec­tion spe­cial­ist. This doesn’t mean you need to pan­ic: it might not be skin can­cer at all – but if it is, it’s always bet­ter to catch it ear­ly, when it’s most treatable.

parts of the body very quick­ly via the blood­stream and lym­phat­ic tract.
Image: When a mole grows, it can ​‘go deep’ and spread to oth­er parts of the body very quick­ly via the blood­stream and lym­phat­ic tract.

How to check for a chang­ing or grow­ing mole?

When self-check­ing your skin (you can down­load our Melanoma Self-Check Guide here), look for any changes in size, shape, colour or ele­va­tion of a mole, includ­ing itch­ing, ten­der­ness, bleed­ing, ooz­ing or crust­ing. Also look for a sore or spot that doesn’t heal, red­ness or a new swelling beyond the bor­der of a mole, or the appear­ance of a lump or bump.

The best way to mon­i­tor any changes to your skin is to take pho­tographs and com­pare them at a lat­er date so you can detect any­thing that has changed or grown — which is exact­ly what a mole check does.

What caus­es a new mole to appear?

A new mole appears when melanocytes (the pig­ment-pro­duc­ing cells in your skin) pro­lif­er­ate, or dupli­cate. Pos­si­ble caus­es of a new mole include: expo­sure to the sun, hav­ing fair skin, a genet­ic pre­dis­po­si­tion to moles and freck­les, or a weak­ened immune sys­tem.3

Almost all moles are benign (non-can­cer­ous), while can­cer­ous moles, includ­ing melanomas, usu­al­ly devel­op as a result of genet­ic muta­tions. The exact cause of benign moles remains unknown.

How­ev­er, new moles in an adult are more like­ly to become can­cer­ous than old moles — around 70% of melanoma cas­es occur in peo­ple aged 50 years and old­er.4 So if you’re old­er and notice a new mole, or if an exist­ing mole changes in appear­ance, it would pay to get it pro­fes­sion­al­ly checked to make sure it’s not cancerous.

The ​‘ugly duck­ling’ rule

Anoth­er use­ful method for spot­ing melanoma is to look for the ​‘ugly duck­ling’. If any mole stands out or looks dif­fer­ent from that of near­by moles, it is the ugly duck­ling, and we advise you to see your GP or a skin can­cer detec­tion ser­vice such as MoleMap to get an expert opin­ion as soon as possible.

It can be a bit scary hav­ing a sus­pi­cious-look­ing mole checked in case it real­ly does turn out to be melanoma. Melanoma is fast-grow­ing and if left untreat­ed, it can spread very quick­ly below the sur­face and through your body.

How­ev­er, on a more pos­i­tive note, melanoma that’s detect­ed ear­ly can almost always be treat­ed suc­cess­ful­ly. In most cas­es, this involves sur­gi­cal removal of the mole and pos­si­bly some skin around it to ensure any melanoma hasn’t spread. To ensure our ser­vice is unbi­ased, we don’t remove moles here at MoleMap, but we can rec­om­mend Der­ma­tol­o­gists who can.

If a mole looks sus­pi­cious, but doesn’t have any imme­di­ate­ly con­cern­ing fea­tures of skin can­cer, we’ll ask you to come back in a few months so we can mon­i­tor any changes. At our skin cancer clinics, our Full Body MoleMap includes unlim­it­ed free spot checks, so we encour­age our patients to take advan­tage of these if you notice any chang­ing moles between appointments.


Sources:
1,4. Melanoma.org.nz: https://www.melanoma.org.nz/be-informed/understanding
2,3. Healthline: https://www.healthline.com/health/new-mole
5,6. https://dermnetnz.org/topics/nodular-melanoma/

MoleMap Team

At MoleMap we check, detect and treat skin cancer. Find out how you can protect your skin at your nearest MoleMap skin cancer clinic.

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MoleMap specialises in skin cancer detection, diagnosis, proactive monitoring and treatment. Want the best protection against melanoma and other skin cancers? Get your skin and moles checked early and often at a MoleMap skin cancer clinic.