Published: 18 Jun 2025

ICD9: 173.32      ICD10: C44.92      ICD11: XH0945

Squamous cell carcinoma (SCC) is a type of cancer that arises from the squamous cells.
Squamous cells are flat, scale-like cells that make up the epidermis (the outer layer of the skin) and also line the mucous membranes and the linings of hollow organs in the body.

Here's a breakdown of key aspects of squamous cell carcinoma:

1. Origin:

Squamous Cells: The cancer originates in the squamous cells, which are essential for protecting the body from the external environment.

2. Types and Locations:

Cutaneous SCC (Skin SCC): This is the most common type. It typically develops in areas exposed to the sun, such as the:
Head (face, scalp, ears)
Neck
Hands
Arms
Legs (less common)
Mucosal SCC: Can occur in the mucous membranes lining various parts of the body, including the:
Mouth
Throat
Larynx (voice box)
Esophagus
Lungs
Anus
Vagina

3. Causes and Risk Factors:

Sun Exposure (UV radiation): The most significant risk factor for cutaneous SCC. Chronic, long-term exposure is particularly dangerous. This is why it's common on sun-exposed areas.
Tanning Beds: Use of tanning beds significantly increases the risk.
HPV (Human Papillomavirus): Certain types of HPV, particularly HPV-16, are strongly linked to SCC in mucosal areas, especially the oropharynx (back of the throat, including tonsils and base of the tongue) and the anus.
Weakened Immune System: People with compromised immune systems (e.g., organ transplant recipients, individuals with HIV/AIDS, those on immunosuppressant medications) are at higher risk.
Chronic Inflammation/Skin Damage: Chronic wounds, burns, scars, ulcers, or exposure to certain chemicals (e.g., arsenic) can increase the risk.
Radiation Exposure: Previous radiation therapy can increase the risk in the treated area.
Smoking and Alcohol: These are major risk factors for SCC in the mouth, throat, and esophagus.
Actinic Keratosis: Precancerous skin lesions called actinic keratoses (also caused by sun exposure) can sometimes progress to SCC.
Fair Skin: People with fair skin, light hair, and blue eyes are more susceptible to sun damage and, therefore, SCC.
Age: The risk increases with age as cumulative sun exposure increases.
Genetic Predisposition: In rare cases, genetic factors may play a role.

4. Symptoms and Appearance:

Skin SCC:
A firm, red nodule.
A flat sore with a scaly crust.
A new sore or raised area on an old scar or ulcer.
A rough, scaly patch that bleeds easily.
May resemble a wart.
Mucosal SCC: Symptoms depend on the location. They may include:
Sores in the mouth that don't heal.
Difficulty swallowing.
Hoarseness.
Pain or bleeding in the affected area.
Change in bowel habits (for anal SCC).

5. Diagnosis:

Physical Exam: A doctor will examine the suspicious area.
Biopsy: A small tissue sample is taken and examined under a microscope by a pathologist. This is the only way to confirm the diagnosis of SCC.
Imaging Tests: If the SCC is large or there's concern about spread, imaging tests like CT scans, MRI scans, or PET scans may be used to assess the extent of the cancer.

6. Treatment:

Treatment options depend on the size, location, and stage of the SCC, as well as the patient's overall health. Common treatments include:

Excisional Surgery: Cutting out the cancerous tissue and a margin of surrounding healthy tissue. This is often the first-line treatment for small, localized SCCs.
Mohs Surgery: A specialized surgical technique where the tissue is removed layer by layer and examined under a microscope until no cancer cells are found. Mohs surgery is often used for SCCs in cosmetically sensitive areas (e.g., face) or those that are difficult to treat.
Curettage and Electrodesiccation (C&E): Scraping away the cancer cells with a curette and then using an electric current to destroy any remaining cells. This is often used for small, superficial SCCs.
Radiation Therapy: Using high-energy rays to kill cancer cells. Radiation therapy may be used for SCCs that are difficult to reach with surgery, for large tumors, or to treat cancer that has spread to lymph nodes.
Topical Medications: Creams or solutions containing medications like imiquimod (an immune response modifier) or 5-fluorouracil (a chemotherapy drug) may be used for very superficial SCCs or precancerous lesions.
Photodynamic Therapy (PDT): Applying a light-sensitizing drug to the skin and then exposing it to a specific type of light to destroy cancer cells.
Targeted Therapy: Drugs that target specific molecules involved in cancer cell growth and survival. These are sometimes used for advanced SCC.
Immunotherapy: Drugs that help the body's immune system fight cancer. These may be used for advanced SCC that has spread.

7. Prognosis:

The prognosis for SCC is generally good, especially when detected and treated early. Most SCCs are curable with surgery or other local treatments.
However, SCC can be more aggressive and can spread to lymph nodes or other parts of the body (metastasis) if left untreated or if it is a more aggressive subtype. Metastatic SCC is more difficult to treat and has a poorer prognosis.
Factors that can affect the prognosis include the size and location of the tumor, whether it has spread to lymph nodes, the patient's immune status, and the specific characteristics of the cancer cells.

8. Prevention:

Sun Protection: This is the most important way to prevent SCC.
Seek shade, especially during peak sunlight hours (10 am to 4 pm).
Wear protective clothing, such as long sleeves, pants, a wide-brimmed hat, and sunglasses.
Use a broad-spectrum sunscreen with an SPF of 30 or higher and apply it liberally to all exposed skin. Reapply every two hours, or more often if swimming or sweating.
Avoid Tanning Beds: Tanning beds emit harmful UV radiation and significantly increase the risk of skin cancer.
HPV Vaccination: The HPV vaccine can help prevent HPV-related SCC, particularly in the oropharynx and anus.
Quit Smoking and Limit Alcohol Consumption: These are important for preventing SCC in the mouth, throat, and esophagus.
Regular Skin Exams: Perform regular self-exams to check for any new or changing moles or skin lesions. See a dermatologist for regular skin exams, especially if you have risk factors for skin cancer.
Treat Precancerous Lesions: Have actinic keratoses and other precancerous skin lesions treated promptly to prevent them from progressing to SCC.

Key Takeaways:

Squamous cell carcinoma is a common type of cancer arising from squamous cells.
Sun exposure is a major risk factor for skin SCC.
HPV is a major risk factor for mucosal SCC in certain locations.
Early detection and treatment are crucial for a good prognosis.
Sun protection and HPV vaccination are important preventive measures.

It is vital to consult a healthcare professional for any concerns or suspected symptoms of squamous cell carcinoma. They can provide accurate diagnosis, treatment options, and personalized advice.