Intraepidermal Squamous Cell Carcinoma

Squamous cell carcinoma is a common type of non-melanoma skin cancer that forms in the flat, scale-like squamous cells on the outermost layer of skin (epidermis). “Intraepidermal” means the cancerous cells are confined to the epidermis, the tissue where they originated. 

Usually, intraepidermal squamous cell carcinoma develops in areas of the body that are frequently exposed to ultraviolet (UV) light from the sun, such as the face, lips, tops of the ears, backs of the hands, arms and lower legs. Less often, the cancer develops on mucosal surfaces, such as those that line the mouth, nose, eyelids, windpipe (trachea), lungs, stomach, intestines, ureters, urethra and urinary bladder. 

Intraepidermal squamous cell carcinoma causes and risk factors

In many cases, intraepidermal squamous cell carcinoma is caused by excessive sun exposure. Other risk factors include: 

• A personal or family history of skin cancer
• Smoking and other forms of tobacco use
• A large burn
• Persistent skin ulcers
• Long-term use of immunosuppressants
• Infection with a certain high-risk strain of human papillomavirus (HPV)
• Fair skin

Intraepidermal squamous cell carcinoma signs and symptoms

The first sign of intraepidermal squamous cell carcinoma is usually a persistent but slow-growing skin lesion, such as a crusted bump or flat red spot. The lesion, which can measure up to a few centimeters in diameter, may sting, burn or feel tender to the touch.

In its early stages, intraepidermal squamous cell carcinoma typically displays a superficial growth pattern. However, if left untreated, it may eventually progress, spread into deeper skin layers and become invasive.

Though rare, intraepidermal squamous cell carcinoma can metastasize or spread, particularly if it originates on the scalp or forehead. In patients who are immunocompromised, the cancer tends to be more aggressive with a greater risk of metastasis.

Intraepidermal squamous cell carcinoma diagnosis

If intraepidermal squamous cell carcinoma is suspected based on the appearance of a lesion, a physician will typically perform a biopsy to confirm the diagnosis and rule out other conditions. If the cancer has advanced and become invasive, the physician may order imaging tests to evaluate its extent and spread.

Intraepidermal squamous cell carcinoma treatment

For a thin, early-stage intraepidermal squamous cell carcinoma, a physician may prescribe a topical cream, which can offer a cure rate of approximately 90%. The options may include imiquimod, an immune system modulator, and 5-fluorouracil, a topical chemotherapy.

In most cases, however, the primary form of treatment for intraepidermal squamous cell carcinoma is surgical removal of the lesion. A common approach is a curettage and electrodessication, which involves the use of a scalpel-like tool (curette) to scrape away the cancer cells. Next, the physician will use an electric needle (electrode) to destroy any remaining cancer cells. Most dermatologists are highly experienced in performing this in-office procedure, which has a cure rate of 90-95%.  

For a deeper or more aggressive tumor, a physician must suggest a scalpel excision to remove the tumor along with a slim margin of surrounding healthy tissue. Another approach is Mohs micrographic surgery, which may be a good option for treating:

• A large tumor (greater than 2 centimeters in diameter)
• Cancer that has spread to the space surrounding a nerve (perineural invasion)
• A recurrent tumor

Mohs surgery is done in conjunction with USF Health. If a physician determines that the tumor is at high risk for distant spread (metastasis), has already metastasized or cannot be surgically removed, radiation treatment may be considered.

Benefit from world-class care at Moffitt Cancer Center

The multispecialty team in Moffitt’s renowned Cutaneous Oncology Program takes an individualized approach to skin cancer treatment. Our goal is to help each patient achieve the best possible outcome and quality of life. If you would like to learn more about intraepidermal squamous cell carcinoma, you can request an appointment with a skin cancer specialist at Moffitt by calling 1-888-663-3488 or submitting a new patient registration form online. We do not require referrals.