Squamous cell carcinoma (SCC) is a very common type of skin cancer, typically affecting sun damaged fair skin.

The majority of SCCs develop in actinic keratoses. These are common small scaly lesions arising on the face, ears and hands of white skinned people who have spent many years outdoors. A thickened or tender keratosis may be a SCC. They may also develop in old burn scars and ulcers.

SCCs vary in size from a few millimeters to several centimeters in diameter. Sometimes they grow to the size of a pea or larger in a few weeks, though more commonly they grow slowly over months or years. They may be tender. Some SCCs appear as sores that fail to heal. A common site is the bottom lip; if a sore has not healed in 3 weeks, see your doctor. SCCs are often crusty and may bleed easily.

Luckily, SCC is not usually a threat to life as secondary spread (metastasis) is uncommon. SCC on the lip or ear can be dangerous however.

In situ squamous cell carcinoma

In situ SCC is also known as "Bowen's disease". "In situ" means the malignant cells are confined to the epidermis, the outside layer of the skin. In situ SCC can persist as such or develop into invasive SCC in which the malignant cells have penetrated into the dermis, the deeper layer of the skin. In situ SCC presents as one or more flat red scaly patches up to several centimeters wide, often found in large numbers on the lower legs.

Keratoacanthoma is an alarming lesion because it grows very quickly. It can develop into a dome-shaped nodule 2 or 3 centimeters in diameter over a few weeks! Keratoacanthomas are rarely dangerous and can even drop off by themselves. Surgical removal is usually recommended, as we cannot predict which ones will fall off and which lesions are true invasive SCCs.

Metastatic SCC

Almost all SCCs remain localized but they can occasionally spread to other sites of the body. These secondary growths are known as metastases. Metastases usually develop in the nearest lymph glands, and are most likely if the original SCC is on the lip or ear. Secondary growths are more difficult to treat than the original skin lesion, as surgery may not always remove them completely.

Treatment

The treatment for a SCC depends upon its type, size, location, the number to be treated, and the preference or expertise of the doctor.

• Excision-The lesion is cut out and the skin is stitched up. This is the most common treatment for invasive SCC.

• Shave, curettage & cautery (and other similar techniques)-Many skin cancers can be successfully treated by shaving off or scraping out the lesion then cauterizing the base. The wound usually heals rapidly without the need for stitches.

• More complex surgery-Patients with larger lesions or one in a difficult site may be referred to a head and neck surgeon or plastic surgeon, who may create a flap or graft to repair the defect after excision.

• Radiotherapy (X-ray treatment)-Radiation treatment can be used for some skin cancers, usually on the face.

• 5-Fluorouracil cream-This cytotoxic cream applied for several weeks often clears in situ SCC. It causes a vigorous skin reaction that may ulcerate. Sometimes the lesion recurs months or years later, when it may be treated the same way or by another method.

• Imiquimod-Imiquimod is an immune response modifier in a cream base. Applied five times weekly for six to sixteen weeks, it will clear most patches of in situ SCC but is not FDA approved for his purpose.

Whatever the chosen treatment, SCC can usually be cured. Occasionally, SCCs come back at the same site, but they can then usually be treated again effectively.

If you have had one SCC treated, you have an increased chance of developing further SCCs.

• Early detection means easier treatment, and less scarring.

• Make sure you protect your skin from the sun at all times.

• Arrange for a complete skin examination from time to time.

Ask your primary care provider to check any persisting or growing lumps or sores.