Definition and Overview

Intraepithelial squamous cell carcinoma (ISCC) is one of the least dangerous types of skin cancer. It starts in cells in the epidermis, which is the upper layer of the skin. It is often not a cause for concern. It rarely spreads to other parts of the body and responds very well to treatment.

Also known as Bowen’s disease, its main sign is a red, scaly patch. Because of this, it is often mistaken for other common skin conditions. These include eczema and psoriasis. The patch can develop in any parts of the body. It is often found in body parts that are usually exposed to the sun. These include the face, neck, and lower legs. However, it can also occur in the groin area and penis (in men).

Although it is slow-growing, skin specialists still advise patients to seek treatment. There is a small risk that it may transform into invasive skin cancer. Invasive skin cancer can spread to other organs, including the bones and brain. When this happens, the disease becomes very difficult to treat.

Causes of Condition

In general, the cause of all types of cancer is unknown. Doctors are not sure what causes normal cells to mutate and cause abnormal growths to form. However, there are factors that increase one’s risk of the condition. For ISCC, these include:

Prolonged exposure to the sun’s harmful UV rays. This is the biggest risk factor for ISCC. People can reduce this risk by:

  • Wearing protective clothing and using broad-spectrum sunscreen.

  • Seeking shade between 10am and 2pm when the sun’s rays are strongest.

A weak immune system - Many people with ISCC have a weak immune system. The immune system is the body’s natural defense against a number of pathogens. It keeps illnesses at bay and helps people stay healthy. However, it can sometimes weaken. Common causes are certain medications and illnesses, such as HIV or AIDS.

Previous cancer treatment - Radiotherapy increases the risk of skin cancer.

Certain infections - Many cases of ISCC in the genital area are due to human papillomavirus (HPV). HPV is a common infection. The majority of the adult population gets it at some point in their lives. HPV is rarely serious. It often goes away on its own and does not cause lasting health problems. However, in some cases, it can increase the risk of genital warts and cancer.

Key Symptoms

The main symptom of the disease is a red, scaly patch on the skin. It can be flat or raised. It can also be itchy at times. The patch can develop in any part of the body.

Who to See and Types of Treatments Available

Any skin changes should be brought to the attention of a dermatologist. ISCC is diagnosed with a skin biopsy. This procedure involves taking a small sample of the affected skin for further analysis. It is often performed using local anaesthetic. Thus, it is painless. The skin sample can be obtained by shaving off the growth using a scalpel. In many cases, stitches are not needed to close the resulting wound. Instead, the biopsy site is covered with sterile dressing until it heals. A punch biopsy is also an option. In this method, a sharp tool is gently pushed down into the biopsy site. It is then slowly rotated to remove a small piece of the affected skin.

Patients with ISCC have a number of treatment options. These include:

  • Active surveillance - This option is best for mild cases. It is also advised if the patient has medical conditions that delay wound healing. Patients are advised to observe the patch for any changes. In many cases, no further treatment is needed because the disease progresses very slowly. However, if there are signs that indicate it is getting worse, other treatments are considered.

  • Topical therapy - Many types of cancers are treated with chemotherapy. The same is true for ISCC. For this treatment, an ointment or cream with chemo agents is applied directly to the skin.

  • Cryotherapy - This treatment destroys skin lesions by freezing them. It involves the application of liquid nitrogen onto the cancer site. This therapy has a 99% cure rate for patients who seek prompt treatment for ISCC.

  • Curettage - This treatment involves scooping out cancer cells using a spoon-shaped instrument. It often results in bleeding, which is treated with heat or electricity (electrocautery).

  • Photodynamic and laser therapies - These procedures use different light sources to kill cancer cells. These include pulsed dye laser and intense pulsed light. They are good options for patients with large areas of skin lesions. Several sessions are often needed to kill all abnormal cells.

The prognosis for ISCC is often excellent. Many cases are cured using treatment methods listed above. However, about 3% of cases progress into invasive skin cancer. This occurs when the condition is left untreated for a very long time.


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  • Perruchoud DL, Varonier C, Haneke E, Hunger RE, Beltraminelli H, Borradori L, et al. Bowen disease of the nail unit: a retrospective study of 12 cases and their association with human papillomaviruses. J Eur Acad Dermatol Venereol. 2016 Sep. 30 (9):1503-6.

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