Worried about a mole that’s new, changing or just looks unusual? Then you’re in the right place – this article outlines the 9 common signs of cancerous moles, with helpful pictures so you know the symptoms to look for.
Most moles are harmless but unfortunately some aren’t – and it can be very difficult to tell if a mole is cancerous with an untrained eye. If you have a mole that’s showing some of the signs of skin cancer below – or if you’re just not sure about it, book an expert full body mole check as soon as possible — because the earlier a cancerous mole is detected, the better the chances of successful treatment.
Read on to find out what warning signs to look for and when you should get a second opinion. Plus, see photos of cancerous moles.
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Most moles or ‘nevi’ are fairly harmless. In general, most Australian adults typically have somewhere between 10 and 40 common, or non-malignant, moles on their body (note that if you have 50 or more moles, you may have a higher risk of melanoma).
Moles are essentially clusters of melanocytes, the pigment-producing cells that increase the production of melanin to protect the skin against potentially harmful UV rays. Melanoma occurs when these melanocytes mutate and begin to divide uncontrollably.
The most common cause of cancerous moles and lesions is excessive exposure to UVA and UVB light (i.e. damage from the sun and sun beds), so the best thing you can do for your skin health is reduce your sun exposure, follow the SunSmart guidelines – and have regular, professional skin checks.
Cancerous moles are caused by damage to the DNA in your skin cells which start to mutate and divide – usually caused by exposure to the sun.
What do normal (non-cancerous) moles look like?
A common mole, also known as a ‘nevus’, is a non-malignant growth on the skin that often appears during childhood or adolescence. They are usually pink, tan, brown or black in colour and can take many different forms, including freckles, moles, skin tags, and seborrheic keratoses. Common moles tend to look alike – they’re uniform in shape and even coloured, ranging from 1mm to 10mm in size.
Almost all of us have moles, although they’re more prevalent in those with lighter or freckly skin. Moles are not normally present at birth, but tend to appear in childhood and early teenage years. Some moles may also lighten or darken with time as we age – especially with sun exposure. Generally speaking, normal moles are stable — they’ll look the same a year from today.
Benign moles are usually pink, brown or tan in colour and fairly similar to each other.
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When self-checking your skin (or the skin of a loved one), look out for anything NEW, CHANGING, or UNUSUAL on both sun-exposed and sun-protected areas of the body.
Melanomas commonly appear on the trunks of men and the legs of women, but they can occur anywhere — even in places that never see the sun, like on the buttocks, the soles of the feet, and the genital area.
Other types of skin cancer such as basal cell carcinoma and squamous cell carcinoma most commonly develop on parts of the body that receive high or intermittent sun exposure, such as on the face, scalp, neck, arms, shoulders and back.
Look out for these 9 common signs of skin cancer when you check your skin:
You notice a new mole
Most moles appear appear during childhood and adolescence, so any new moles that appear if you’re aged over 25 (and especially if you’re aged over 50) could potentially be cancerous and should be checked out, especially if you notice the mole changing.
You have a mole that’s increasing in size
Moles can grow slowly as you get older, but a rapid or sudden change in size, shape or colour is something to be concerned about and may indicate the presence of fast-growing melanoma. Moles that are larger than 6 mm in size (the diameter of a pencil eraser) should be checked regularly. Cancer moles can be smaller, but they don’t usually stay that way and will grow over time.
Any mole that increases in size should be checked out by a professional.
You have a mole that’s asymmetrical in shape
As a general rule, most normal, non-cancerous moles are fairly symmetrical in shape - whereas most problem moles are asymmetrical or lop-sided. Asymmetry in moles is one of the ‘red flags’ for skin cancer, so ensure you have any unusually-shaped moles checked by your GP or skin cancer detection service.
The edge of a mole has become notched or ragged
The borders of an atypical (cancerous) mole are often irregular, notched and/or ‘hazy’ - symptoms that become more pronounced as time goes on. Bear in mind that the edges of lentigos (freckles) are often asymmetrical and ragged too - which is why it always pays to have your skin checked by professionals who know the difference.
These pictures of cancerous moles show how notched, scalloped or blurred edges may look.
The surface of your skin is becoming rough, scaly or ulcerated
Small, rough or scaly patches on your skin can be actinic keratosis (solar keratosis) which is generally caused by too much sun, and commonly occurs on the head, neck, or hands, but can be found elsewhere. They can become cancerous over time, so it pays to get these checked regularly for changes. However, if a mole is ulcerated, you should get it checked immediately – it is highly likely to be a melanoma and has a higher risk of spreading than other melanomas.
You have a mole that’s darkening or changing in colour
Most normal moles are tan, brown, or the same colour as your flesh and are also uniform in appearance. One part of the mole isn’t necessarily lighter or darker than any other. If a mole appears to be multicoloured - in that it has areas that are dark brown, blue, black or white, and even red - you should get a second opinion from MoleMap or your GP. This can be a sign of superficial spreading melanoma, a common form of melanoma.
A normal mole can come in a lot of different shades, but if it’s variegated in colour like in the cancerous moles image above – or turning from brown to black – you should get it checked straight away.
You have a mole that’s itchy, tingling, weeping or bleeding
Most skin cancer moles don’t hurt, but there are warning signs of melanoma, including itchiness, tingling, bleeding or weeping. Just like the rest of the skin on your body, a mole can become itchy, or get injured and bleed as a result of injury – that’s usually nothing to worry about. However, moles that bleed or ooze fluid without being injured may be cause for concern – you should get these checked by experts just as soon as you can.
A mole is becoming raised or develops a lump within it
This can be a symptom of nodular melanoma (see cancerous moles picture below), a particularly fast-growing and dangerous form of melanoma skin cancer. The key giveaway is that it's raised, often symmetrical, firm to touch, and is changing or growing progressively. Any raised, firm or growing spots should be professionally checked as a precaution.
As these images show, nodular melanoma is usually raised, often symmetrical, firm to the touch and grows or changes within a few months.
You have a mole or spot that looks different from the others – the ‘ugly duckling sign’
Most normal moles on your body will look similar in appearance, while melanomas often stand out like ugly ducklings in comparison. These can be larger, smaller, lighter or darker when compared to surrounding moles – or they may be isolated without any surrounding moles. That’s why it’s important to not only check your moles, but also to compare them – this is a vital part of any professional mole- mapping and monitoring service such as a Full Body MoleMap.
Other helpful guides developed by dermatologists for detecting atypical moles and skin cancer are the ABCDE and EFG rules, as well as the Scan Your Skin method – you can check them out here . You can also find our helpful guide for self-checking your skin and read on for the answers to other frequently asked questions about skin cancer moles.
Can a normal mole become cancerous?
The short answer is yes. For adults, new moles and sudden changes to existing moles can be a sign of melanoma. According to Yale School of Medicine, approximately 70 percent of melanomas appear on normal skin, while 30 percent originate in a pre-existing mole in which changes in color, size, and/or shape have occurred.
Can I detect a cancerous mole myself?
We thoroughly recommend regular self-checks so you can get to know your skin and moles. Be sure to check your skin from head to toe, including the palms of the hands and soles of your feet. Don’t forget that cancerous moles can be found on parts of the body not exposed to the sun. It’s not just new moles you’re on the look out for, check all existing moles too. But please bear in mind that no matter how vigilant you are about checking your skin, many of the signs of skin cancer are very difficult to see with an untrained eye - especially in the early stages.
Note also that a single examination of your skin isn’t enough to assume a mole will remain normal. One of the major indications of skin cancer moles is that they continue to grow and change shape and colour, and these symptoms generally become more pronounced over time – which is why we recommend a mole check to track changes in your skin and moles over time.
Can a doctor tell if a mole is cancerous just by looking at it?
If the skin cancer is starting to advance, then yes, the symptoms may be obvious to the naked eye. However, early melanoma symptoms aren’t always visible at a glance.
That’s why a group of dermatologists pioneered the Full Body MoleMap, which involves taking high-resolution, close-up images of any at-risk moles and spots, and comparing them at subsequent appointments. This methodology can improve the chances of detecting any potential atypical moles and skin cancers much earlier than visual checks – because the earlier skin cancer is found, the better the chances of beating it.
What are the risk factors for getting cancerous moles?
The most common risk factors for melanoma skin cancer are:
fair and/or freckly skin that burns easily
fair, blonde or red hair
having been sunburnt in the past or used sunbeds
having a lot of moles (50+)
being over 50 years old
leading an outdoor lifestyle or having high doses of intermittent sun (e.g. on holiday)
a personal or family history of melanoma or other skin cancers
How often should I get my skin checked for cancerous moles?
The latest statistics from the US show that patients whose melanoma is detected early have a 99% five-year survival rate. This drops to 66% if melanoma reaches the lymph nodes, and 27% if it spreads to distant organs.11 All good reasons to have a skin cancer check every year.
Remember, if you’re worried about a mole, don’t chance it: check it. It may just save your skin – and your life, as early detention of cancer is crucial for successful outcomes.
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.
