Skin Cancer - Squamous Cell Carcinoma

Introduction

Squamous cell carcinoma is the second most common type of skin cancer.  It occurs when the squamous cells in the skin grow abnormally and out of control.  Exposure from ultraviolet (UV) radiation from the sun is the most frequent cause of squamous cell carcinoma.

There are several types of squamous cell carcinomas, and it has many different appearances.  Squamous cell carcinoma is a relatively slow growing type of non-melanoma skin cancer. 
Squamous cell carcinoma needs to be treated.  If detected and treated early, it has a very good cure rate.  However, untreated or aggressive types of squamous cell carcinoma can cause significant disfigurement, spread to other parts of the body, and cause death. 

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Anatomy

Your skin covers your body and protects it from the environment.  Your skin is composed of three major layers, the epidermis, dermis, and subcutaneous tissue.  The epidermis is the outermost layer of your skin.  It protects your inner skin layers.  The epidermis is made up of protein containing cells called keratinocytes, also referred to as squamous cells.  The keratinocytes form at the bottom layer of the epidermis and move upward to the outer layer.  They eventually wear off and are replaced by the next layer of cells.  The epidermis also contains melanocytes.  This type of cell contains color pigments called melanin.  The lowest layer of the epidermis is composed of basal cells.
 
The dermis is your second layer of skin.  It is made up of connective tissue and provides structure.  It is composed of collagen and various elements that give your skin strength and elasticity.  The dermis contains hair cells, sweat glands, and sebaceous glands that secrete oils to hydrate the skin.
 
Subcutaneous tissue composes your inner most layer of skin.  Subcutaneous tissue contains fat cells.  The fat cells insulate your body and make your skin appear plump and full.  Below the subcutaneous tissue are fat tissues, your muscles, and bones.
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Causes

Squamous cell carcinoma results when the squamous cells (keratinocytes) in the epidermis of the skin grow abnormally and out of control, instead of dividing in an orderly manner.  The abnormal keratinocytes spread deeper into the next layer of skin, the dermis, and attack the tissues.  There are several factors that cause squamous cell carcinomas, but the majority of cases are caused by overexposure to UV rays from the sun.
 
Squamous cell carcinomas are a relatively slow growing type of skin cancer.  However, some forms of squamous cell carcinoma are aggressive and can spread to other parts of the body, including fat tissues, lymph nodes, and internal organs.  Squamous cell carcinomas can have several different appearances. 
 
Squamous cell in situ, also called Bowen’s disease, is the earliest form of squamous cell carcinoma.  The cells are “in situ,” meaning that the cancer is in the epidermis and has not spread to the dermis.  Actinic keratosis is a precancerous skin condition.  Actinic keratosis should be removed because in a very small percentage of cases, actinic keratosis can turn into squamous cell carcinoma. 
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Symptoms

Squamous cell carcinoma commonly appear on areas of skin that received frequent sun exposure, such as the face, ears, neck, lip, scalp, and the back of the hands.  They can occur on the genitals, anal area, tongue, and in the mouth.  They can also develop in scars, sores, or burns.
 
Squamous cell carcinoma may start out growing slowly, followed by a period of intense growth.  Squamous cell carcinoma has a variety of appearances.  It may begin as a small wart-like growth.  The growth may be cone-shaped with the base of the cancer being beneath the surface of the skin.  The growth may be gray or a yellow-brown color. 
 
Squamous cell carcinoma may originate in a burn, scar, or skin injury.  It may appear as a small firm bump with a reddened base.  It may look like a nodule or a flat growth.  The surface may look scaly or crusty.
 
Squamous cell carcinoma in situ appears as red scaly or crusted patches.  They may grow over one-half inch.  Actinic keratoses are small rough spots that may be pink-red or skin colored.  They typically appear in areas that have been exposed to the sun.  Actinic keratoses are slow growing.  They may go away on their own and come back. 
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Diagnosis

You should call your doctor if you notice a change in the color, texture, or appearance of your skin or if you have a sore that does not heal or bleeds.  Your doctor can diagnose squamous cell carcinoma by examining the growth and performing a biopsy of the suspected area.  A biopsy is a simple procedure that takes tissue for examination.  There are a few types of biopsy methods. 
 
After numbing your skin, your doctor may perform a shave, punch, incisional, or excisional biopsy.  A shave biopsy removes the top layers of the skin.  A punch biopsy uses a round punch to cut through all of the layers of skin to remove a tissue plug.  An incisional biopsy removes a part of the tumor, and an excisional biopsy removes the entire tumor.  In some cases, the incisions will be stitched. 
 
The tissue samples are sent to a laboratory for examination.  Request to have your tissue sample examined by a dermapathologist.  A dermapathologist is a pathologist with special training in skin cell disorders.  The dermapathologist will determine if your tissue sample contains squamous cell carcinoma.
 
Your doctor’s office will contact you with the results when they receive them.  Skin cancer is classified based on how far it has spread.  Stages are classified as 0-4, with 4 being a more serious cancer.  There is more than one staging system so make sure that you and your doctor are referring to the same one.
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Treatment

Squamous cell carcinomas that are detected and treated early have very good cure rates.  The goal of treatment is to remove all of the cancer cells.  There are several types of removal methods.  The treatment that you receive depends on the size, location, and stage of your cancer.  Most treatments can take place in your doctor’s office and use a local anesthesia.
 
Electrodesiccation and curettage is a procedure that removes the surface layer of skin cancer and gently burns (“cauterizes”) its base to destroy any remaining cells.  A simple excision is a method that cuts out the tumor and some healthy cells around it.  The incision is stitched back together.  Cryosurgery is a treatment method that uses liquid nitrogen to freeze and kill cancer cells. 
 
A specialized technique, Mohs micrographically controlled surgery, is used to treat large skin cancers or skin cancers that have come back.  For Mohs surgery, the doctor removes a layer of skin containing the cancerous squamous cells and examines it under a microscope right away.  The process is repeated until the skin samples are found to be free of cancer cells.  The advantages of Mohs surgery are that only the minimum amount of tissue necessary is removed and the specimens are carefully examined.  Mohs surgery is associated with high cure rates.
 
If your cancer has spread, radiation and chemotherapy treatments may be necessary.  Skin grafting and reconstructive surgery may be necessary after the removal of large squamous cell carcinomas.  Scarring after skin cancer removal is common.  Cosmetic surgery techniques can improve the appearance of scars.  Some people choose to cover their scars with make-up.
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Prevention

You should perform a full body skin and mole inspection monthly.  It may be helpful to use a mirror or have someone else look at areas of your skin that are difficult for you to see.  Promptly report any suspicious moles or areas of skin to your doctor.  It is important to have your doctor perform regular full body skin and mole checks.  You should make and attend all of your follow up appointments.
 
You may be able to prevent skin cancer by limiting the amount of time that you are exposed to the sun.  Anyone that is exposed to the sun should wear a sunblock that blocks both UV A and B sunrays.  A sunscreen is a different product.  Sunscreens allow you to spend a longer amount of time in the sun without burning than you could if you were not wearing sunscreen. 
 
Most doctors recommend a sunblock that blocks both UV A and B rays and a sunscreen with a sun protection factor (SPF) of at least 15.  A SPF of 15 provides protection from burning for 150 minutes.  Sunscreen should be reapplied every 1 ½ hours or so depending on your activity level.
 
It is important to discard old sunblock and sunscreen.  Their effectiveness is reduced over time.  You should apply sunblock and sunscreen even in the winter.  Remember to apply it to all of your skin that is exposed including your hands, ears, lips, lower legs, the backs of your knees, and the tops of your feet.
 
It is beneficial to avoid being in the sun between the hours of 10 AM and 4 PM, when the sun’s rays are the strongest.  A good way to remember this is that if your shadow is shorter than you are tall, it is not a good time to be out in the sun.  You can still be outside, but seek shade.
 
If you must spend time in the sun, it is smart to wear hats with a wide brim and tightly woven fabrics that are especially made to block the sun.  Some clothing is rated for its SPF factor. Your doctor is happy to refer you to such clothing suppliers. 
 
Wear sunglasses that block UVA and B sunrays.  Wrap-around styled sunglasses protect your eyes and your eye area.  Sun-related cancers can occur inside of the eye.  Wear sunglasses and make sure that your eye doctor checks for cancer at each of your eye exams.
 
You should avoid sun tanning outside and sun tanning lamps or booths.  Tanning beds and lamps give off harmful UV rays and can cause sunburns.  An alternative is to use self-tanning products or spray on cosmetics.
 
You should stop smoking and avoid cancer causing chemicals.  If your job requires exposure to cancer causing agents, follow all of the safety instructions associated with the chemical’s use.  Wear protective masks and gear as instructed.
 
Teach your children about protecting their skin in the sun.  This is important because many skin cancers result from sunburns that occur before age 18.  Make sure that your children learn to apply and reapply sunblock and sunscreen when they are playing outdoors.
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Am I at Risk

Risk factors may increase your likelihood of developing squamous cell carcinoma, although some people that experience this skin cancer may not have any risk factors.  People with all of the risk factors may never develop squamous cell carcinoma; however, the likelihood increases with the more risk factors you have.  You should tell your doctor about your risk factors and discuss your concerns.

Risk factors for squamous cell carcinoma:

_____ People with light colored skin (Caucasians), blue eyes, green eyes, gray eyes, blond hair, or red hair have an increased risk for developing skin cancer.  However, people with darker complexions and dark hair may get skin cancer as well, but they have a lower risk.
_____ People that spend a lot of time in the sun, such as construction workers, farmers, fishermen, lifeguards, sunbathers, and outdoor sport enthusiasts have an increased risk for skin cancer.
_____ Receiving multiple severe sunburns in childhood or as a teenager is a big risk factor for developing skin cancer.
_____ People that have had skin cancer before are at risk for developing skin cancer again.
_____ Cigarette smoking can contribute to skin cancer.  The tar in cigarettes is a known cancer causing agent.
_____ Exposure to cancer causing chemical agents, such as oils, tars, and arsenic (found in some herbicides) is associated with an increased risk for squamous cell carcinoma.
_____ Chronically injured skin is a risk factor for squamous cell carcinoma.
_____ People with suppressed immune systems, such as organ transplant recipients or people that have AIDS, have an increased risk for squamous cell carcinoma.
_____ Not wearing a sunblock for UV rays A and B while in the sun increases the risk of skin cancer.
_____ Your risk for squamous cell carcinoma increases with age.  Most cases develop in people that are middle aged or elderly, but it certainly can develop in younger people.
_____ People that sunburn easily are at a higher risk for developing skin cancer. 
_____ People with multiple moles have a higher risk of developing skin cancer.
_____ People with freckled skin have a higher risk of developing skin cancer.
_____ Artificial tanning lights used in tanning booths, beds, and lamps have harmful UV rays and increase the risk of skin cancer.
_____ Some people have a genetic predisposition to squamous skin cancer.
_____ Overexposure to X-rays or other forms of radiation increases the risk of skin cancer.
_____ People with rare genetic disorders, such as nevoid carcinoma syndrome, xeroderma pigmentosum, or Bazex syndrome, have an increased risk for developing squamous cell carcinoma.
_____ People with the human papilloma virus (HPV) carry an increased potential for developing squamous cell carcinoma.
_____ People that received X-ray treatment for acne in the 1950s have a higher risk of developing squamous cell carcinoma.
_____ Actinic keratosis is a skin condition that can develop into squamous cell carcinoma.  Actinic keratosis results from overexposure to the sun.  It looks like rough dry patches on the skin.  Your doctor should remove actinic keratosis.
_____ People treated with Psoralen and ultraviolet light for chronic psoriasis have an increased chance of developing squamous cell carcinoma and other types of skin cancer.

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Complications

Untreated squamous cell carcinoma may grow quite large and result in disfigurement, such as the loss of an ear or nose.  The cancer may turn into a large open sore that is vulnerable to infection.  Squamous cell carcinoma can spread to other parts of the body, including fatty tissues, lymph nodes, and internal organs.  It can cause death.  Squamous cell carcinomas located on the lip, ears, palm of the hand, or sole of the foot have the highest risk of spreading.  People with squamous cell carcinoma are at risk for developing new skin cancers in the future.
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Advancements

Researchers have discovered a link between some types of HPV and squamous cell carcinoma.  If you have HPV, you should ask your doctor about your risk and preventative screenings. 

Researchers are testing medications to treat squamous cell carcinoma.  Scientists have learned how UV light causes normal cells to become cancerous.  They are using this knowledge to find ways to treat skin cancer.
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This information is intended for educational and informational purposes only. It should not be used in place of an individual consultation or examination or replace the advice of your health care professional and should not be relied upon to determine diagnosis or course of treatment.

The iHealthSpot patient education library was written collaboratively by the iHealthSpot editorial team which includes Senior Medical Authors Dr. Mary Car-Blanchard, OTD/OTR/L and Valerie K. Clark, and the following editorial advisors: Steve Meadows, MD, Ernie F. Soto, DDS, Ronald J. Glatzer, MD, Jonathan Rosenberg, MD, Christopher M. Nolte, MD, David Applebaum, MD, Jonathan M. Tarrash, MD, and Paula Soto, RN/BSN. This content complies with the HONcode standard for trustworthy health information. The library commenced development on September 1, 2005 with the latest update/addition on February 16, 2022. For information on iHealthSpot’s other services including medical website design, visit www.iHealthSpot.com.