Skin growths

Picture of skin growths on back

Skin growths

There are a number of different lumps & bumps that can appear on the skin. Most cause no harm, but some can be cancerous and life threatening. We summarise some common growths below

Skin tags

Skin tags are benign (not cancerous) growths that are usually small and flesh-coloured, hanging from the skin on narrow stalks. It is not really known why they form in some people but not others, but they are commonly found in the armpits, groin and on the neck, where the skin gets rubbed by clothing or against other skin. It used to be common practice to tie a piece of thread around the base and allow the skin tag to shrivel up and fall off – this is now discouraged as infection can result.

Skin tags can be easily and quickly removed under local anaesthetic and will usually leave barely visible scars


Sebaceous cysts are very common skin swellings, which are generally thought to arise from the hair glands. For this reason they can occur on most parts of the body, and are commonly found on the scalp. The cyst can vary from being pea-sized to golf ball sized or larger, and can sometimes produce a thick creamy discharge. The skin over the cyst usually appears normal, although close inspection may reveal a tiny hole (punctum), which connects to the cyst. Occasionally they can get infected and become painful, red and hot. This usually settles with antibiotics. 

Whilst sebaceous cyst are benign, they can be a nuisance, can be painful, and can be embarrassing if on a cosmetically sensitive and noticeable area such as the face. 

The cysts can be removed with surgery often leaving a scar slightly shorter than the width of the cyst. The removal of the cyst, however, may leave a slight depression from where it has been excised although this is usually not very noticeable. Depending on the size and site of the cyst, the surgery can usually be performed under local anaesthetic. Up to 1 in 10 cysts can recur, which may need further procedures to remove them. 

Read more about cyst removal here


A mole, (also called naevus), is a benign skin growth that can occur anywhere on the skin. They can be present from childhood, and generally increase in number. It is quite normal to have a number of moles, although a large number (for example over 100) may point to other underlying conditions. 

Moles are usually light brown or tan in colour, although may also be normal flesh coloured, with a smooth surface and a smooth border. They usually do not itch or cause any problems. It is quite common to see hair arising from the mole, although plucking the hairs out is discouraged as it can sometimes cause infection. 

Although moles are benign, they can occasionally turn cancerous and become melanomas (see below). For this reason, any changes within a mole should be taken seriously. Moles can also occur on cosmetically sensitive areas such as the face, and can sometimes be removed to leave a less obvious scar.

Laser can occasionally be used to remove moles, but usually the mole will need to be removed with surgery. This can often be performed under local anaesthetic. The mole may be removed by shaving or curetting (scraping) it off, leaving a scar that is flush to the skin. This has the advantage that the scar is usually the same size as the mole, but the disadvantage that the hairs or even the mole may grow back, and is unsuitable for some types of mole. Cutting out the whole mole will also remove the hairs, but leaves a scar that is slightly longer than the original mole (usually 2-3 times longer). Your surgeon should be able to discuss these options with you in more detail

Lipomas (fatty growths)

Lipomas are benign growths of fat that form lumps just under the skin. There is no specific cause for these growths. They are usually painless, and can slowly grow to produce sizeable lumps that can be easily felt or even seen.Some people may get just one lipoma in a lifetime, whilst some can form a number of lipomas throughout their life. 

They can be removed using surgery, usually leaving a scar slightly shorter than the lipoma. A depression in the skin may be left where the lipoma has been removed. They can recur, and may then need further procedures to remove them. Occasionally, very large lipomas can be mostly removed by liposuction. This leaves smaller scars, but may have higher risks of recurrence

Malignant melanoma

Melanomas are malignant skin growths. They can occur at any age, but are rare in childhood. Some melanomas can form from pre-existing moles, but most arise from previously normal looking skin and can occur anywhere. They don’t usually cause pain, although can itch, bleed or crust over. It is firmly believed that they are primarily a result of sun exposure, and may be linked to childhood sunburn. 

Any changes in a mole should raise suspicion – most changes are normal, but some can be the first signs of a mole turning into a melanoma. The ‘ABCDE’ signs to look for are:

Asymmetry – the melanoma may be iregular in shape rather than rounded as for a benign mole 

Border – the edge of the melanoma may be irregular rather than smooth 

Colour – classically, melanomas are jet black in colour although may be dark brown or of patchy colouring. 

Diameter – a diameter greater than 6mm raises suspicion

Elevation – as they grow, melanomas may raise and become dome-shaped

Small, dark patches may also appear near to the melanoma and the surface skin may become broken and ulcerated. 

These growths have the potential to metastasize, whereby they move to nearby glands, the liver, lungs, spine or brain, so if you think you have a melanoma, you should get it checked as soon as possible

Read more about malignant melanoma here

Squamous Cell Carcinoma

Squamous cell carcinomas (SCCs) are malignant skin growths that become increasingly common with increasing age. They are usually caused by sunlight and tend to occur on sun-exposed parts of the body. SCCs are also fairly common in immunocompromised people, such as transplant patients that need to take medication to suppress the immune system. 

Squamous cell carcinomas can arise from previously normal looking skin, or from a pre-malignant growth such as Actinic Keratosis (see below). SCCs usually do not cause pain, but can bleed or crust over. They can grow quite quickly and, as they grow larger, tend to ulcerate. 

Their appearance can vary from being small, dry-looking growths to large, dome-shaped fleshy or crusted growths. 

They can occasionally spread elsewhere, including nearby glands, lungs or liver. For this reason, SCCs are removed with surgery

Read more about squamous cell carcinomas here

Rodent Ulcers

Rodent ulcer, also called Basal Cell Carcinoma (BCC) is the commonest form of cancer, with over 100,000 new cases per year in the UK and 800,000 new cases per year in the USA. It is estimated that one third to one half of the Australian population will get rodent ulcers at some time in their life. 

There is a strong link between rodent ulcer formation and sun exposure, but it may take years for them to form. A common scenario is that a person with rodent ulcers may remember spending time living in a hot climate 20 or more years previously. People at more risk are those who sunburn easily, and/or have pale skin, blue eyes, red hair and Celtic ancestry. 

Rodent ulcers tend to appear on sun-exposed areas such as the face, but also commonly appear on other parts of the body. They vary from being tiny ‘pimple-like’ growths to large, raised growths that can itch, crust over and bleed. Pain is rare. 

Despite their name, these carcinomas do not behave like most other cancers. Rodent ulcers tend to grow very slowly, and can take years to get to only a centimetre in size. Whilst there have been reports of them spreading to the glands, this is incredibly rare and many doctors consider them as non-spreading growths. Rodent ulcers do need treating, though, as they can grow into important structures such as eyes, ears, nerves or even bone, or cause recurrent bleeding if they grow into vessels. 

Read more about rodent ulcers here

Actinic Keratosis

Actinic keratosis (AK) is a very common skin growth that is due to sun exposure. Whilst actinic keratosis in itself is harmless, they are pre-malignant, in that they have the potential to turn into a cancer (a squamous cell carcinoma). These growths are more common in later life, and tend to occur on sun-exposed areas such as the hands and face. 

Actinic keratosis is usually 5-10 mm in diameter, and looks dark pink-red in colour with a dry, flaky surface. Whilst they can occur singly, it is also common to have many actinic keratoses at any one time

Read more about actinic keratosis here


The information above is for general information only and does not replace that of a medical specialist – if you have a growth that you are worried about, you should consult a medical specialist at your earliest opportunity

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