Medical Definition Of Skin Cancer
- Medical Author: Melissa Conrad Stöppler, MD
Reviewed on 7/23/2021
Skin cancer is a type of cancer that begins in cells of the skin. Skin cancer is the most common type of cancer in humans. Ultraviolet light exposure from the sun or tanning beds is the greatest risk factor for developing skin cancers.
The most common type of skin cancer is a basal cell cancer. These begin in the so-called basal cells of the upper layer of skin, the epidermis. They tend to form in sun-exposed areas of skin. Basal cell cancers do not usually spread to other parts of the body , and they can typically be cured if they can be surgically removed. Squamous cell cancers are cancers of the cells that form the flattened cells of the epidermis. Like basal cell cancers, they usually occur in areas exposed to sunlight. Squamous cell cancers also can typically be cured if they can be surgically removed. Basal cell cancers often appear as a waxy or pearly bump on the skin. Squamous and basal cell cancers can appear as flat lesions, reddened nodules, or scaling or scar-like areas.
Melanomas are less common but are a more serious form of skin cancer. Melanoma can develop anywhere on the body. Melanomas often appear as new moles or moles that appear to have changed in appearance. Melanomas can spread to other parts of the body and can be fatal if not treated early.
Other less common types of cancer in the skin include Kaposi’s sarcoma, Merkel cell cancer, and lymphoma of the skin.
Differences Between Cancer Cells And Normal Cells
Cancer cells differ from normal cells in many ways. For instance, cancer cells:
- grow in the absence of signals telling them to grow. Normal cells only grow when they receive such signals.
- ignore signals that normally tell cells to stop dividing or to die .
- invade into nearby areas and spread to other areas of the body. Normal cells stop growing when they encounter other cells, and most normal cells do not move around the body.
- tell blood vessels to grow toward tumors. These blood vessels supply tumors with oxygen and nutrients and remove waste products from tumors.
- hide from the immune system. The immune system normally eliminates damaged or abnormal cells.
- trick the immune system into helping cancer cells stay alive and grow. For instance, some cancer cells convince immune cells to protect the tumor instead of attacking it.
- accumulate multiple changes in their chromosomes, such as duplications and deletions of chromosome parts. Some cancer cells have double the normal number of chromosomes.
- rely on different kinds of nutrients than normal cells. In addition, some cancer cells make energy from nutrients in a different way than most normal cells. This lets cancer cells grow more quickly.
How Is Melanoma Diagnosed
If you have a mole or other spot that looks suspicious, your doctor may remove it and look at it under the microscope to see if it contains cancer cells. This is called a biopsy.
After your doctor receives the skin biopsy results showing evidence of melanoma cells, the next step is to determine if the melanoma has spread. This is called staging. Once diagnosed, melanoma will be categorized based on several factors, such as how deeply it has spread and its appearance under the microscope. Tumor thickness is the most important characteristic in predicting outcomes.
Melanomas are grouped into the following stages:
- Stage 0 : The melanoma is only in the top layer of skin .
- Stage I: Low-risk primary melanoma with no evidence of spread. This stage is generally curable with surgery.
- Stage II: Features are present that indicate higher risk of recurrence, but there is no evidence of spread.
- Stage III: The melanoma has spread to nearby lymph nodes or nearby skin.
- Stage IV: The melanoma has spread to more distant lymph nodes or skin or has spread to internal organs.
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The Most Common Types Of Pre
A Common Precancer Actinic keratosis is the most common precancer that forms on skin damaged by chronic exposure to ultraviolet rays from the sun and/or indoor tanning. Solar keratosis is another name for the condition. AKs result from long-term exposure to ultraviolet radiation Symptoms depend on whether it is a cancer or pre-cancer and what kind of vulvar cancer it is. Vulvar intraepithelial neoplasia. Most women with vulvar intraepithelial neoplasia have no symptoms at all. When a woman with VIN does have a symptom, it is most often itching that does not go away or get better NYU Langone doctors use several therapies to treat an actinic keratosis, a precancerous lesion that can turn into a squamous cell skin cancer. Some of these treatments may also be used for very early basal cell or squamous cell carcinoma. Which therapy you undergo is largely a matter of personal preference If your cancerdoes come back at some point, your treatment options will depend on where the cancer is and what treatments youve had before. If the cancer comes back just on the skin, options might include surgery , radiation therapy , or other types of local treatments
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What Is Precancerous Skin Growth

Precancerous skin growths develop on skin that has a lot of sun exposure over time without proper protection. While its not considered cancer yet, it can turn into it in the future. While many forms of precancerous skin growths form after the age of 40, it can happen at an earlier age, especially for those of us living in Florida where we are outside in a lot of sunshine.
Actinic keratosis is the most common type of precancerous growth. Some people say an AK feels rough, like a spot of sandpaper on the skin. Many oncologists consider AKs as early squamous cell cancers . If left untreated, AKs are likely to progress into nonmelanoma skin cancer.
If precancerous skin growths are left untreated, they may result in one of the following types of skin cancer:
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What Are The Signs Of Melanoma
Knowing how to spot melanoma is important because early melanomas are highly treatable. Melanoma can appear as moles, scaly patches, open sores or raised bumps.
Use the American Academy of Dermatology’s “ABCDE” memory device to learn the warning signs that a spot on your skin may be melanoma:
- Asymmetry: One half does not match the other half.
- Border: The edges are not smooth.
- Color: The color is mottled and uneven, with shades of brown, black, gray, red or white.
- Diameter: The spot is greater than the tip of a pencil eraser .
- Evolving: The spot is new or changing in size, shape or color.
Some melanomas don’t fit the ABCDE rule, so tell your doctor about any sores that won’t go away, unusual bumps or rashes or changes in your skin or in any existing moles.
Another tool to recognize melanoma is the ugly duckling sign. If one of your moles looks different from the others, its the ugly duckling and should be seen by a dermatologist.
When Do Cells Become Cancerous
Most of the time, the answer to how long it may take for a precancerous cell to become cancerous will vary. The answer also depends on the type of cell thats involved.
In one study that looked at 101 people with abnormal cell changes of the vocal cords, 15 of them went on to develop invasive cancer.
One of those had mild dysplasia, one had moderate dysplasia, seven had severe dysplasia, and six had carcinoma in situ. In 73% of these people, their precancerous lesions became invasive cancer of the vocal cords within one year. The rest of them developed cancer years later.
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A Primer On Skin Cancer
Malignant melanoma, especially in the later stages, is serious and treatment is difficult. Early diagnosis and treatment can increase the survival rate. Nonmelanoma skin cancers include basal cell carcinoma and squamous cell carcinoma. Both are common and are almost always cured when found early and treated. People whove had skin cancer once are at risk for getting it again they should get a checkup at least once a year.
Gender Ethnic/racial And Life Span Considerations
The incidence of skin cancer is more common between ages 30 and 60, with the majority of lesions occurring in patients over 50. However, younger people are now more likely to develop skin cancer, perhaps because of greater exposure to the sun. Children rarely have the disease, although the incidence increases with each decade of life. The ratio of European Americans to African Americans among people who develop skin cancer is 20:1. Males are more likely than women to develop BCC and SCC . People with fair skin and freckles are at especially high risk.
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Skin Cancer Prevention In Portland
Most skin cancers result from too much sun exposure. The ultraviolet A rays can cause premature wrinkling, brown age spots while the ultraviolet B rays cause sunburns. Both types of radiation, UVA and UVB, are harmful and can cause skin cancer. It is essential to protect your skin from these damaging rays in order to prevent skin cancer. Not only do sunburns increase skin cancer, a tan is a sign of sun damage and will increase your risk of skin cancer.
Knowledge Is Your Best Defense
What Is Skin Cancer?
Skin cancer is the out-of-control growth of abnormal cells in the epidermis, the outermost skin layer, caused by unrepaired DNA damage that triggers mutations. These mutations lead the skin cells to multiply rapidly and form malignant tumors. The main types of skin cancer are basal cell carcinoma , squamous cell carcinoma , melanoma and Merkel cell carcinoma .
The two main causes of skin cancer are the suns harmful ultraviolet rays and the use of UV tanning beds. The good news is that if skin cancer is caught early, your dermatologist can treat it with little or no scarring and high odds of eliminating it entirely. Often, the doctor may even detect the growth at a precancerous stage, before it has become a full-blown skin cancer or penetrated below the surface of the skin.
Americans will develop skin cancer by age 70.
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Benign Tumors That Develop From Other Types Of Skin Cells
- Seborrheic keratoses: tan, brown, or black raised spots with a waxy texture
- Hemangiomas: benign blood vessel growths, often called strawberry spots
- Lipomas: soft growths made up of fat cells
- Warts: rough-surfaced growths caused by some types of human papilloma virus
Most of these tumors rarely, if ever, turn into cancers. There are many other kinds of benign skin tumors, but most are not very common.
Cancer Prevention Is Key

Generally speaking, your doctor will make an educated guess to determine whether precancerous lesions may develop into cancer. Your doctor will consider several factors, including family history, body mass index, and tobacco use, to evaluate your risk of cancer.
At Ezra, we have created a five-minute questionnaire to assess your cancer risk factors. If you decide to be proactive about your health, Ezra offers several cancer screening solutions using imaging techniques such as MRI and low-dose CT.
The Ezra full-body MRI screens a total of 14 organs for cancer in less than 60 minutes. This technique is safe, painless, and affordable.
With the Ezra Full Body Plus package, an additional five-minute low-dose CT imaging exam of your chest will be performed. This package is especially valuable for detecting head, neck, chest, abdomen, and pelvic cancer. Make an appointment today.
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What Should I Do If I See Changes In My Skin
“The next step up from self-detection is to talk to your primary care doctor or your dermatologist,” Dr. Meyer said. “If for some reason you don’t have a primary care doc who’s comfortable with skin checks, I always recommend a dermatologist once a year just to take a look from head to toe and make sure that those moles, those lesions all look the same.”
When Should I Call My Doctor
You should have a skin examination by a doctor if you have any of the following:
- A personal history of skin cancer or atypical moles .
- A family history of skin cancer.
- A history of intense sun exposure as a young person and painful or blistering sunburns.
- New or numerous large moles.
- A mole that changes in size, color or shape.
- Any mole that itches, bleeds or is tender.
A note from Cleveland Clinic
Receiving a diagnosis of melanoma can be scary. Watch your skin and moles for any changes and seeing your doctor regularly for skin examinations, especially if youre fair-skinned, will give you the best chances for catching melanoma early when its most treatable.
Last reviewed by a Cleveland Clinic medical professional on 06/21/2021.
References
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How Common Is Melanoma
Melanoma accounts for only about 1% of all skin cancers, but causes the great majority of skin cancer-related deaths. Its one of the most common cancers in young people under 30, especially in young women.
Melanoma incidence has dramatically increased over the past 30 years. Its widely accepted that increasing levels of ultraviolet exposure are one of the main reasons for this rapid rise in the number of melanoma cases.
How Does Cancer Develop
Cancer is caused by certain changes to genes, the basic physical units of inheritance. Genes are arranged in long strands of tightly packed DNA called chromosomes.
Cancer is a genetic diseasethat is, it is caused by changes to genes that control the way our cells function, especially how they grow and divide.
Genetic changes that cause cancer can happen because:
- of errors that occur as cells divide.
- of damage to DNA caused by harmful substances in the environment, such as the chemicals in tobacco smoke and ultraviolet rays from the sun.
- they were inherited from our parents.
The body normally eliminates cells with damaged DNA before they turn cancerous. But the bodys ability to do so goes down as we age. This is part of the reason why there is a higher risk of cancer later in life.
Each persons cancer has a unique combination of genetic changes. As the cancer continues to grow, additional changes will occur. Even within the same tumor, different cells may have different genetic changes.
Fundamentals of Cancer
Cancer is a disease caused when cells divide uncontrollably and spread into surrounding tissues.
Cancer is caused by changes to DNA. Most cancer-causing DNA changes occur in sections of DNA called genes. These changes are also called genetic changes.
A DNA change can cause genes involved in normal cell growth to become oncogenes. Unlike normal genes, oncogenes cannot be turned off, so they cause uncontrolled cell growth.
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For More Information About Skin Cancer
National Cancer Institute, Cancer Information Service Toll-free: 4-CANCER 422-6237TTY : 332-8615
Skin Cancer Foundation
Media file 1: Skin cancer. Malignant melanoma.
Media file 2: Skin cancer. Basal cell carcinoma.
Media file 3: Skin cancer. Superficial spreading melanoma, left breast. Photo courtesy of Susan M. Swetter, MD, Director of Pigmented Lesion and Cutaneous Melanoma Clinic, Assistant Professor, Department of Dermatology, Stanford University Medical Center, Veterans Affairs Palo Alto Health Care System.
Media file 4: Skin cancer. Melanoma on the sole of the foot. Diagnostic punch biopsy site located at the top. Photo courtesy of Susan M. Swetter, MD, Director of Pigmented Lesion and Cutaneous Melanoma Clinic, Assistant Professor, Department of Dermatology, Stanford University Medical Center, Veterans Affairs Palo Alto Health Care System.
Media file 5: Skin cancer. Melanoma, right lower cheek. Photo courtesy of Susan M. Swetter, MD, Director of Pigmented Lesion and Cutaneous Melanoma Clinic, Assistant Professor, Department of Dermatology, Stanford University Medical Center, Veterans Affairs Palo Alto Health Care System.
Continued
Media file 6: Skin cancer. Large sun-induced squamous cell carcinoma on the forehead and temple. Image courtesy of Dr. Glenn Goldman.
What Can You Expect During A Skin Cancer Screening
During a skin cancer screening, the doctor will look at your skin from head to toe. This includes your scalp and between your fingers and toes. If youve noticed any moles or other lesions that are new, changing, or causing symptoms like itching or pain, tell your doctor so that area can be examined closely.
The doctor will also examine lesions that look different from others, including ones that have irregular borders, multiple colors, or are bigger than 6 millimeters in diameter. They might use a dermatoscope to inspect individual lesions. A dermatoscope is a handheld device that allows the doctor to evaluate an area of the skin much more closely.
As part of the screening, your doctor may recommend a biopsy, which involves taking a sample of skin to test for cancer. It takes a few minutes to perform this type of biopsy, and the biopsy wound should heal in 1 to 2 weeks. The doctor then sends the biopsy sample to a lab for testing, and you will receive the results from your doctor in a week or 2 after that. If cancer has been found, your doctor will arrange for additional treatment, such as surgery. If the skin cancer is more advanced or if there is evidence that the cancer has spread to other areas of the body, then your doctor will refer you to an oncologist for further treatment.
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