Online Dermatologist > Squamous Cell Carcinoma

Medically reviewed by The Dermatologists and written by Dr. Alexander Börve

Last updated on May 28, 2024

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.

Other forms of skin cancer: Malignant melanoma, Basal cell carcinoma

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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

Key conditions to consider and differentiate from SCC include:

• Actinic Keratosis: Often a precursor to SCC, characterized by rough, scaly patches on sun-exposed areas of the skin.
• Basal Cell Carcinoma: The most common type of skin cancer, which appears as a slightly transparent bump on the sun-exposed skin.
• Melanoma: A more dangerous form of skin cancer distinguished by its rapid change and dark pigmentation.
• Burns: These can sometimes mimic the appearance of skin cancers due to their scar-like features.
• Scar Tissue: Often confused with SCC due to its thick, irregular texture.
• Pyoderma Gangrenosum: A non-cancerous condition that causes large, painful ulcers, and could be mistaken for SCC.

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.

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Should I seek medical care?

Skin biopsy is the only way to diagnose skin cancer. You dermatologist will remove part of or the entire affected area and examine it with a microscope. The findings will be communicated in a biopsy report. With early detection and treatment, SCC is highly curable.

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 usually the treatment option for SCC. Actinic keratoses are usually treated with freezing with liquid nitrogen but also photodynamic therapy (PDT) applications and medical creams.

Excision
Your dermatologist can usually perform an excision during an office visit. The procedure involves numbing the affected area and cutting out the tumor and skin around it. The doctor then looks at the removed skin and examine if the surrounding skin is free of cancer cells. More skin may be removed if the biopsy suggests otherwise.

Mohs surgery
Mohs surgery is specialized surgery with the highest cure rate for difficult-to-treat squamous cell cancers. The surgeons cut out the tumor and a small amount of surrounding normal-looking skin. The surgeon then examines the removal under a microscope and continue remove very small amount of skin until no cancer cells is examined.

Other treatments include radiation, chemotherapy cream, laser treatment, photodynamic therapy and curettage and electrodesiccation.

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Source:

Howell JY, Hadian Y, Ramsey ML. Squamous Cell Skin Cancer. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024. Updated March 27, 2024. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441939/

American Academy of Dermatology. Squamous cell carcinoma. Available at: https://www.aad.org/public/diseases/skin-cancer/types/common/scc

American Cancer Society. Treating Squamous Cell Carcinoma of the Skin. Available at: https://www.cancer.org/cancer/types/basal-and-squamous-cell-skin-cancer/treating/squamousl-cell-carcinoma.html.

Skin Cancer Foundation. Squamous Cell Carcinoma (SCC) – Recurrence, Prevention, and Early Detection. Available at: https://www.skincancer.org/skin-cancer-information/squamous-cell-carcinoma/scc-recurrence-and-prevention