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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.
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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