Squamous cell carcinoma is the second most common skin cancer. It usually appears as a rough, scaly or crusted bump on skin that has had years of sun, and it often looks like a sore that will not heal. Found early it is removed and cured. Left alone it grows deeper, and a small share spread. A seborrheic keratosis is a common, harmless growth that looks stuck onto the skin, like a piece of wax or a small barnacle. They are not cancer and they do not become cancer. The reason to see a doctor is to be sure that is what you are looking at.
The same eight facts on every condition comparison.
It is a skin cancer of keratinocytes.
It arises from the main cells of the outer skin.
It often looks crusted or ulcerated.
It may be a growing scaly lump, persistent sore or tender patch.
Most are treated successfully.
Some can invade deeply or spread to lymph nodes.
Risk is assessed individually.
Size, depth, site and immune status guide care.
It is a benign growth.
Surface skin cells form a waxy, warty or stuck-on growth.
Color varies.
It can be tan, brown, gray or almost black.
It is not a precancer.
These growths become more common with age.
Uncertain lesions are tested.
Tissue is examined before any destructive treatment if the appearance is unclear.
Squamous cell carcinoma in situ Flat red scaly patch, surface only.
Invasive squamous cell carcinoma Generated illustration. Firm, crusted or ulcerated bump.
Keratoacanthoma Fast-growing dome with a central crater.
Classic seborrheic keratosis Raised, waxy, stuck-on growth.
Stucco keratosis Small white-gray bumps on the legs.
Dermatosis papulosa nigra Small dark bumps on the face.
DNA changes allow abnormal surface skin cells to multiply, commonly after long-term ultraviolet damage. In invasive squamous cell carcinoma, the cancer grows through the epidermal boundary into the dermis.
A benign overgrowth of surface skin cells creates a localized plaque. Keratin and sometimes pigment collect in the growth, giving it a waxy, rough or stuck-on appearance.
Squamous Cell Carcinoma. Usually appears in older adults after cumulative sun damage; immunosuppression can lead to earlier disease.
Seborrheic Keratosis. Usually appears in adult life and becomes increasingly common with age.
Squamous cell carcinoma starts when DNA damage makes skin cells grow out of control. Ultraviolet light is the main cause.
Seborrheic keratoses are harmless growths of skin cells that become more common with age.
Fair skin that burns easily is inherited and raises the risk.
They often run in families.
Evidence labels come from each condition’s own treatment list.
A strong urea cream can soften and flatten the rough white growths that scatter over the lower legs, called stucco keratoses, if the roughness is what bothers you. It smooths the surface rather than removing the growth, and it has to be used continuously. It does nothing for thick, dark, stuck-on growths elsewhere.
Wart treatments are often tried on these because the surface looks similar. Salicylic acid can thin the rough top layer, but it does not clear the growth, and it irritates the normal skin around it. The bigger problem is that it is usually being used on something nobody has examined.
This is aftercare, not treatment. A thin layer of plain petroleum jelly over a treated spot keeps the scab soft and gives the neatest healing, under a small dressing rather than an adhesive strip. It does nothing to a growth that is still there.
Daily mineral sunscreen over a spot that has just been treated stops the temporary mark from darkening and helps it fade faster, which matters most on the face, chest and hands. It will not remove a growth or stop new ones forming. Sun is only one of several things that drive these, and age and family history matter more.
A high-strength peroxide solution applied in clinic was approved for raised growths on the face and body. It cleared some growths, often needed repeat visits, and commonly caused stinging, crusting and pigment change. It was withdrawn from sale in the United States, so in practice removal is done by hand rather than with a liquid.
The tumor is removed a layer at a time and each layer is checked under the microscope during the same appointment, so the surgeon stops as soon as the edges are clear. It gives the highest cure rate and takes the least normal skin, which is why it is used on the face, ears, lips, hands, feet and genitals, and for large, recurrent or aggressive tumors. It is a long appointment rather than a difficult one.
The standard removal: the tumor is cut out with a margin of normal skin around it and the wound is stitched closed, usually in one visit under local anesthetic. It cures the large majority of straightforward tumors on the trunk, arms and legs. The margins are checked afterwards rather than during, so occasionally a second procedure is needed to clear an edge.
The tumor is scraped out with a small loop and the base is sealed with an electric current, repeated a few times in one sitting. It is quick and effective for small, thin, low-risk tumors on the trunk and limbs. It is not used on the face, on large or recurrent tumors, or anywhere depth matters, because nothing is sent for margin checking and it leaves a round pale scar.
A quick freeze in clinic, used for actinic keratoses and occasionally for a small patch of carcinoma in situ. It is a treatment for the step before this cancer, not for the cancer itself. Freezing an invasive tumor leaves cells behind at depth and hides what is happening under a healing crust.
A light-activated cream treatment for the earliest forms only — actinic keratoses and some cases of carcinoma in situ. It treats a whole patch of sun-damaged skin at once and heals with a good cosmetic result. It has no role in an invasive tumor, and using it on one delays proper removal.
Nothing else on this page happens without it. Even an experienced dermatologist with a dermatoscope cannot settle this by looking, and the report says far more than yes or no — how deep it goes, how aggressive the cells look, whether it is tracking along a nerve. Those details choose the treatment. It takes a few minutes under local anesthetic and leaves a small wound. A biopsy does not make cancer spread.
The growth is scraped off with a small curette and the base sealed with a fine electric tip. It is controlled and shallow, which is why it is often preferred for small facial growths and for the dark facial growths common on deeper skin tones. Scraping first still gives tissue that can be examined if there is doubt.
A few seconds of liquid nitrogen makes flatter growths blister and lift off over a week or two, and it is the quickest way to treat several at once. It destroys the growth, so nothing can be examined afterward, which is why it is not used on anything with a question attached. It is used cautiously on the face and on deeper skin tones, because the pigment cells are sensitive to cold and it can leave a pale spot.
When a growth is changing, bleeding on its own, or simply looks unlike your others, part or all of it is taken after numbing and examined under a microscope. It is the only way to be certain, and the threshold for doing it is deliberately low, because the cost of a small biopsy is trivial next to missing a melanoma. An irritated growth is one of the commonest reasons a benign growth ends up being sampled.
The growth is numbed and shaved off level with the skin in a few seconds. It is the method of choice when there is any question about what a growth is, because it produces tissue that can be sent to the laboratory. It leaves a flat mark that fades over months, and it does not stop new growths appearing elsewhere.
An ablative laser can vaporise a growth precisely and is sometimes used when several need treating on the face. Like freezing, it destroys the tissue, so it is only for growths already confirmed as harmless. It is the most expensive of the options and it is not better than a curette for a single growth.
Most skin squamous cell carcinomas are cured with appropriate treatment, but they should not be left untreated. Some grow or spread more quickly, especially with immune suppression. Follow-up helps detect recurrence and additional skin cancers.
Seborrheic keratoses appear slowly, change slowly, then stay. Two departures deserve attention: one growth that starts changing - growing, darkening, bleeding on its own, or itching persistently - and a sudden crop of many new ones over weeks to months.
A small percentage reach the lymph nodes
A small percentage spread to nearby lymph nodes and occasionally further. Higher risk with large or deep tumors, ear or lip sites, recurrence, and immunosuppression.
Catching on clothing makes it flare
A growth caught by clothing, a strap or a waistband can turn red, swollen, itchy, crusted or sore, and can bleed. That is an irritated seborrheic keratosis. It settles, but it looks alarming and often prompts removal or a sample.
Arrange prompt assessment of a persistent scaly, crusted, enlarging or non-healing lesion, especially if tender or bleeding.
Have a new, changing, bleeding or uncertain growth assessed; skin cancer can sometimes resemble a harmless stuck-on growth.
It is a real cancer and treated as one. Most cases are cured by removal, which is why the emphasis is on early checks. Untreated, it grows into deeper structures and a small share reach lymph nodes. How serious it gets depends on how long it is left.
Usually weeks to months rather than days or years. The keratoacanthoma variant can appear and enlarge within a few weeks. In immunosuppressed people growth can be much faster, which is why the advice for that group is more urgent.
It depends on the site and how the tumor looks under the microscope. Mohs is generally used on the face, ears, lips, hands, feet and genitals, and for large, recurrent or aggressive tumors. Tumors on the trunk, arms and legs usually get a standard excision.
The treated one can recur, though that is uncommon when margins were clear. Far more common is a new skin cancer elsewhere, because the same damage runs through the rest of the skin. Hence follow-up after a cure.
It substantially raises the odds - many people who have one keratinocyte cancer develop another within a few years. Hence skin checks, daily sun protection and treating actinic keratoses.
Most people do not. Scans and node assessment are reserved for high-risk features - large size, deep invasion, growth along nerves, recurrence, immunosuppression - or an enlarged node. Your dermatologist decides from the pathology report and examination.
It could be, which is why it should be looked at rather than diagnosed at home. Melanoma is sometimes mistaken for a seborrheic keratosis, and a dermatoscope resolves most of these in seconds. The concerning features are change in size, shape or color, bleeding without being knocked, an irregular edge, and a growth unlike your others. Book rather than watch.
Age and family history account for nearly all of it. They accumulate steadily from the forties onward, and someone whose parents had many will develop many. A genuinely sudden crop over weeks to months, especially with itching, is different and worth examining.
No. Removal deals with that growth, not the age and inherited tendency behind it, so new ones can keep appearing elsewhere. That is expected, not a failed removal.
Often, at least for a while. A flat spot darker or paler than nearby skin is common, and dark marks usually fade over months. Pale marks can be permanent and are more noticeable on deeper skin tones, so ask about the method and do a test spot before treating a large area. Daily sunscreen on the treated spot makes a real difference.
Most likely it caught on clothing, a strap or a razor and became an irritated seborrheic keratosis. They look far worse than they are and they settle. Still have it looked at - an irritated growth is one of the harder ones to be sure about by appearance, and a growth that bled with nothing catching it is a different question.
As many as you and your doctor think sensible, usually in sessions rather than all at once. It is normally considered cosmetic, so ask about cost first. On the face, and particularly on deeper skin tones, start with a small test area and see how it heals.
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