Squamous Cell Carcinoma: Definition, Causes, Risk Factors, Symptoms, Diagnosis and Treatment

Excessive sun exposure can lead to carcinomas, the most common type of skin cancer.

Carcinomas are also known as non-melanoma skin cancers. A carcinoma is a cancerous tumor of the epithelial tissue, the tissue under the skin.

Epithelial tissue is also present in the digestive tract, blood vessels, and other organs, which means squamous cell carcinomas can affect body areas other than the skin.

In most cases, people are over the age of 50 when they are diagnosed with carcinoma. Statistics show that 90 percent of carcinomas occur in people with fair skin.


Health professionals define different carcinomas by the type of cell they occur.

Basal cell carcinoma or BCC CCB

It develops in basal cells, which are round skin cells that lie deep in the skin’s epidermis below the squamous cells. They form the base layer of the epidermis, which meets the dermis.

BCC is unlikely to spread, but doctors who suspect that an individual has this type of carcinoma will refer them for further evaluation.


Squamous cell or squamous cell carcinoma

Squamous cells make up most of the top layer of the skin, which people call the epidermis. These cells are flat and to scale.

Doctors suspect SCC will provide a more urgent referral as BCC is more likely to spread.

The SCC is, however, much rarer than the BCC. It is responsible for less than 20 percent of non-melanoma skin cancers.

Causes of squamous cell carcinoma

Exposure to ultraviolet (UV) radiation from sunlight is the leading cause of squamous cell carcinoma and other skin cancers.

Some people are more sensitive to UV light than others and are more vulnerable to the effects of sunlight in the development of cancer.

Additional UV exposure from tanning beds and UV curing lamps in nail salons, for example, can also increase a person’s risk.

UV radiation can cause DNA damage in skin cells, leading to mutations during cell division and possibly resulting in skin cancer.

Risk factor’s

Factors and characteristics that increase carcinoma risk include a personal history of skin cancer and radiation treatment for any form of cancer, particularly in childhood.

A family history of cancer could also contribute.

Other risk factors include:

  • You have numerous irregular or large moles or freckles.
  • Tendency to burn before tanning.
  • Have fair skin, blue or green eyes, or blonde, red, or light brown hair.
  • Autoimmune diseases, such as systemic lupus erythematosus.
  • Hereditary conditions, such as xeroderma pigmentosum and nevoid basal cell carcinoma syndrome, also known as Gorlin syndrome.
  • A weakened immune system, possibly due to HIV, receiving an organ transplant or taking immunosuppressive medications.
  • Taking medications that make the skin photosensitive, such as vandetanib (Caprelsa), vemurafenib (Zelboraf), and voriconazole (Vfend).
  • Human papillomavirus (HPV) infection, particularly in people with weakened immune systems.

Actinic keratosis, which consists of raised, rough growths that cause precancerous changes in skin cells, is a specific risk factor for squamous cell carcinoma.

These growths are the most common type of precancerous skin lesion.

Without treatment, this condition can turn into skin cancer.

While UV radiation is the leading risk factor for squamous cell carcinoma, the subsequent skin damage can also increase the risk of this type of carcinoma:

  • Skin burns.
  • Chemical damage
  • Exposure to X-ray radiation.

BCC can also develop after exposure to X-ray radiation in childhood, although this is a much less common cause of carcinoma than UV exposure.


BCC and squamous cell carcinoma are skin tumors and share some characteristics. However, these skin lesions can vary in appearance.

Some carcinomas retain a flat surface and, as a result, can resemble healthy skin. Anyone with unexpected injuries should visit a healthcare professional for a check-up and monitoring.

Aside from its presence, a lump or injury often doesn’t cause noticeable symptoms in its early stages. As a result, it may not be apparent until it becomes relatively large, when it may itch, bleed, or cause pain.

Basal cell carcinoma

BCC usually presents as a shiny abscess, a small red or pink lump that grows slowly.

A shiny, pearly, or waxy-looking edge may form after months or years.

A raised rim often sounds in a central ulcer, and abnormal-looking blood vessels may become visible. These can emerge as blue, brown, or black areas.

Alternatively, they can be pinkish growths, or pale or yellow areas that resemble scars.

Due to this wide range of issues, getting an accurate diagnosis from a doctor is essential.

BCC may appear scaly and often causes recurrent scabbing or bleeding. It may resemble a healing scab when a scab forms, but sores can still occur.

People with BCC often seek medical advice when they discover a sore that will not heal.

Squamous cell or squamous cell carcinoma

Squamous cell carcinoma usually presents as persistent, thick, rough, scaly patches or a firm pinkish lump with a flat, scaly, crusty surface.

These injuries can bleed if someone hits, scratches, or scrapes them. While they sometimes look like warts, they can also appear as open sores with a crusted surface or raised edge.

It is vital to seek the opinion of a healthcare professional regarding the development of new growths or changes in pre-existing growths or sores on the skin.


To diagnose any form of skin cancer, a doctor will perform a physical exam. They will examine the skin lesion and record its size, shape, texture, and other physical attributes.

They can also take a photo of the injury for specialist review or record its current size and appearance for future comparison.

The doctor will often check the rest of the body for additional skin symptoms.

They will also take a medical history focused on the injury and any related conditions, such as sunburn.

A physician will urgently refer suspected cases of squamous cell carcinoma for specialized investigation and treatment due to its tendency to spread.

Tumors suspected of BCC do not require such an urgent referral, as they are less likely to spread.

If they think a lesion may be cancerous, the doctor will likely perform a biopsy. There are four different types of skin biopsy, all of which involve the removal of tissue from the skin for laboratory evaluation.

The different types are:

  • Shave biopsy: Using a sharp surgical blade, the doctor shaves the upper layers of skin cells, usually down to the dermis, but sometimes more profound. This type of biopsy often causes bleeding, but it can be stopped by cauterizing the wound.
  • Needle biopsy: The doctor uses a sharp, hollow surgical tool that resembles a small cookie cutter to remove a circle of skin under the dermis. A person may need a single stitch to close the resulting wound.
  • Incisional biopsy: The doctor removes some of the growth with a scalpel, cutting a full-thickness wedge or slice of skin. This type of biopsy often needs more than one stitch later.
  • Excisional biopsy: The doctor removes all the growth and some of the surrounding tissue with a scalpel. The resulting wound generally requires stitches.

After taking the tissue sample, the doctor will send it to a pathology lab for examination under a microscope. The pathology team will evaluate the cells for cancerous features. If there is cancer, they will determine its type.

Generally, no further research is necessary for people with BCC, as it is rarely spread. However, people with squamous cell carcinoma may need to have tests for cancer in other tissues.

Additional tests usually include imaging and may consist of:

  • X-rays.
  • CT scans.
  • MRI scans.
  • Positron emission tomography (PET).


Treatment options for both types of carcinoma are similar, although the medical team emphasizes monitoring people with squamous cell carcinoma for signs of metastasis.

The specific treatment (s) your doctor recommends will depend on the carcinoma’s size, type, stage, and location. The doctor will also consider additional factors, such as possible side effects and the individual’s preference.

Either way, treatment will likely involve a team of healthcare professionals, including dermatologists and surgical, medical, and radiologic cancer specialists.

Treatment options may include the following:

Curettage and electrodesiccation is a standard procedure to remove a small lesion. The doctor uses a small, sharp spoon- or a ring-shaped instrument called a curette to scrape off the carcinoma before burning the site with an electric needle.

It may take more than one round of curettage and desiccation to kill cancer cells completely.

Surgical excision:  A surgeon removes the lesion, sometimes in a procedure known as Mohs surgery, which works best on larger lesions.

The surgeon checks for cancer cells during this procedure after removing each layer.

Mohs surgery is beneficial in cases that require the removal of as little skin as possible, such as injuries near the eye.

Doctors will also use it for injuries with a high risk of recurrence.

Cryosurgery: Doctors may use this procedure for small tumors, which involves applying liquid nitrogen to freeze and kill cancer cells. The lesion then blisters and falls off in the weeks after treatment.

Topical chemotherapy:  The doctor may apply chemicals or drugs that kill cancer cells directly to the skin.

The chemotherapy option is 5-fluorouracil, including Carac, Efudex, Fluoroplex, and other drugs. A doctor may apply this anticancer drug to the skin once or twice a day for several weeks.

Because this local treatment does not reach other body systems, it does not cause the side effects that often occur with chemotherapy for different types of cancer.

Non-chemotherapy treatment options include imiquimod cream, which is available under Aldara and Zyclara. This cream is sufficient for small CCBs, and it works by encouraging the body to produce interferon, which causes the immune system to attack the tumor.

A doctor can also inject interferon directly into the injury.

Radiation therapy:  The treatment team targets large or difficult-to-remove lesions with focused radiation.

Photodynamic Therapy (PDT): Doctors sometimes use this two-step therapy to treat BCC. They will apply a light-sensitive cream to the affected area of ​​the skin and then expose it to a vital light source.

Light has a particular wavelength of blue light, which leads to the death of carcinoma cells.

Since the skin remains sensitive to light for the next 48 hours, people should avoid UV light to minimize the risk of severe sunburn.

Laser therapy for carcinoma:  This involves using different types of lasers to kill cancer cells. Some lasers vaporize or remove the top layer of the skin, destroying any lesions present there.

Other lasers are non-ablative and penetrate the skin without removing the top layer. There is some evidence of its success in treating small and superficial CCBs.

The United States Food and Drug Administration (FDA) has not yet approved laser therapy for BCC. However, doctors can sometimes use it as secondary therapy if other treatments have not been successful.