Squamous Cell Carcinoma

Symptoms | Differential Diagnosis | What Can I Do? | High-Risk Features of SCC | Seeking Medical Care | Treatment

Squamous cell carcinoma (SCC) is the second most common form of skin cancer after basal cell carcinoma. About one million new cases of this skin cancer are diagnosed in the United States each year.

It originates from the abnormal and rapid growth of squamous cells, which are found in the outer layers of the skin. When caught early, most SCCs are curable.

quamous Cell Carcinoma (SCC) on the skin showing a raised, ulcerated lesion with a central crust, indicative of an aggressive form of skin cancer

The disease is more common in men and in older people, but may also occur in younger people. Patients with fair skin and high levels of sun exposure are at most risk of developing develop skin cancer. The presence of sun damaged lesions are called actinic keratoses, which are often appear as multiple pink, rough lesions found on sun exposed sites that may indicate a higher risk for developing cancer. Actinic keratoses are, therefore, sometimes be termed “pre-malignant.”

Anyone who has had one squamous cell tumor has an increased chance of developing another, especially in the same skin area or nearby. That is usually because the skin has already suffered irreversible sun damage.

Symptoms of Squamous cell carcinoma (SCC)

Squamous cell carcinoma is often found in chronic sun-exposed areas of the head, neck, lower legs and back of the hands. You can also get squamous cell carcinoma in chronic wounds and scars from burns and radiation therapy. When caused by an HPV infection, it may start under a nail and destroy the nail.

The most common symptom is a rough lump or blemish anywhere on the skin. The lesions are often skin colored or pale red, and sometimes covered with hard scales. They usually do not itch.

Symptom of squamous cell carcinoma (SCC): Rough, raised lump on the skin with pale red color and hard scales.

In the early stage (squamous cell carcinoma in situ), the cancer grows superficially on the skin. A blush spot appears, sometimes with small wounds and flaking. Such lesions are sometimes misdiagnosed as eczema patches.

Squamous cell carcinoma (SCC): skin lesion on the lower lip, possibly an early stage of SCC, characterized by a raised, reddish nodule

In the second stage (invasive SCC), the cancer grows deeper into the skin and appears as a well-defined flesh-colored or slightly red nodule. The flaking often continues. In some cases, the cancer presents itself as a tumor or ulcer covered with crusts. The cancer can then spread to other parts of the body.

Squamous cell carcinoma (SCC) on the skin, characterized by a red, inflamed lesion with an ulcerated center

Differential Diagnosis

Several skin conditions can mimic squamous cell carcinoma (SCC), making accurate diagnosis essential. These include:

• Actinic Keratosis – A common precursor to SCC, presenting as rough, scaly patches on sun-exposed areas.

• Basal Cell Carcinoma (BCC) – The most prevalent skin cancer, typically appearing as a pearly or translucent bump with rolled edges.

• Melanoma – A potentially aggressive skin cancer, often pigmented, asymmetric, and prone to rapid change.

• Burns – Healed burns may resemble SCC due to scarring and changes in skin texture.

• Scar Tissue – Thickened, irregular scars may be mistaken for cutaneous malignancies.

• Pyoderma Gangrenosum – A rare inflammatory skin disorder causing painful ulcers, which can be confused with ulcerative SCC lesions.

What can I do?

You should protect your skin from the sun and indoor tanning. Avoid using tanning beds – people who use tanning beds have a much higher risk of getting squamous cell carcinoma.

Examine your skin often. If you find new nodules, blushing changes or ulcers on your skin that do not heal on its own, you should seek medical care. These lesions should always be examined more closely. In many cases, they are benign, but it is important to rule out the possibility of skin cancer.

Should I seek medical care?

A skin biopsy is the only definitive way to diagnose squamous cell carcinoma (SCC). Your dermatologist will remove part or all of the suspicious area and examine the tissue under a microscope. The results will be detailed in a biopsy report.

Early detection and treatment are key—when caught early, SCC is highly curable and outcomes are generally excellent.

High-Risk Features of Cutaneous Squamous Cell Carcinoma

Certain characteristics of cutaneous squamous cell carcinoma (SCC) are associated with a higher risk of aggressive behavior and poor outcomes. These high-risk features include:

• Perineural Invasion: The presence of cancer cells along or within a nerve track within the skin, which can lead to more invasive growth and potential spread.
• Thickness of Lesion Greater than 2 mm: Thicker lesions are more likely to invade deeper layers of skin and potentially spread to other parts of the body.
• Lesion on the Ear: SCCs located on the ear are particularly concerning due to the ear’s proximity to lymph nodes and the potential for early spread.
• Poorly Differentiated Lesion: These lesions show cells that lack the typical features of normal cells and tend to be more aggressive and less responsive to standard treatments.

Treatment

Surgical excision is the most common and effective treatment for squamous cell carcinoma (SCC). For precursor lesions such as actinic keratoses, treatment options often include cryotherapy with liquid nitrogen, photodynamic therapy (PDT), or topical medical creams.

Excision

Your dermatologist can typically perform this procedure during an office visit. It involves numbing the affected area and surgically removing the tumor along with a margin of surrounding skin. The excised tissue is examined under a microscope to ensure that no cancer cells remain at the margins. If cancer cells are detected, additional skin may need to be removed.

Mohs Micrographic Surgery

Mohs surgery offers the highest cure rate for high-risk or difficult-to-treat SCCs. This technique involves removing the tumor in thin layers and immediately examining each layer under a microscope. The surgeon continues this process until no cancer cells are seen, preserving as much healthy tissue as possible.

Additional Treatment Options

Other available treatments may include:

• Radiation therapy

• Topical chemotherapy creams (e.g., 5-fluorouracil)

• Laser therapy

• Photodynamic therapy (PDT)

• Curettage and electrodesiccation (scraping the tumor and using electricity to destroy remaining cells)