The appearance of both SCC and its precursors can vary in color and size. SCC is often crusty or scaly, and may occasionally bleed Figure 02. Actinic, or “solar” keratosis is a precancerous condition that may eventually develop into SCC if left untreated. It is usually less than 1 cm (.4 inches) in diameter, often has a scaly surface, and can vary in color from pink, red, or tan-brown. Because it may be the same color as the skin, it is sometimes noticeable only by its sandpaper-like texture. Sometimes it resembles a wart, and horn-like structures may develop on the surface. Occasionally, SCC can develop and grow rapidly if left untreated.
Another precencerous lesion is called actinic cheilitis. Actinic cheilitis gives a white, scaly appearance to the lip. It often involves the lower lip, which receives the most sun exposure. This, too, may develop into SCC if left untreated.
Figure 02. Actinic keratosis
SCC that remains in the epidermis is known as Bowen’s disease, or squamous cell carcinoma in situ Figure 03. Bowen’s disease may appear as a persistent, reddish-brown, scaly plaque that can resemble psoriasis or eczema, and may occasionally bleed. Although it does not invade deeper into the skin, it is a true skin cancer that requires treatment.
Figure 03. Bowen’s disease
More advanced carcinoma that has spread beyond the epidermis is often nodular, and may have open sores.
SCC can also develop inside the mouth, where it appears as a white, thickened area that may develop non-healing sores.
Lesions may also appear on the genital and anal regions, where they are often associated with a history of genital warts.
Table 1. Symptoms of Squamous Cell Carcinoma
Color: flesh-colored, pink, red, or brown Size: from microscopic to several centimeters in diameter, though usually less than 1 cm (.4 in) Sandpaper-like texture Scaly Crusty May grow horn-like structures May occasionally bleed May form open sores On lips: white, scaly On mucous membrane (such as in mouth): whitish, thickened patch
Light-skinned individuals with a cumulative history of prolonged or intense sun exposure are at an increased risk of skin cancer. The incidence of skin cancer and its precursors increase dramatically with age. People who tend to burn rather than tan, those with light skin color, blond or red hair, freckles, and blue eyes are at especially high risk.
SCC tends to develop on people who have had excessive sun exposure: farmers, lifeguards, construction workers, outdoor enthusiasts, and others with a history of severe or frequent sunburns. Those who live at high altitudes or in areas where the ozone layer has thinned are also at increased risk. Immunocompromised people, including those with organ transplants, have a significantly increased risk of developing skin cancer.
Various other environmental factors have been implicated in SCC development.
- Tobacco: smokers have a 50% higher risk than nonsmokers
- Treatment with UV radiation, as for psoriasis
- Treatment with x-rays
- Arsenic exposure
Skin cancer can also develop within burns or other chronic, nonhealing wounds.
Some people have an inherited predisposition to skin cancer, such as those with the genetic syndromes xeroderma pigmentosum (a hypersensitivity to UV light) and albinism (a deficiency or absence of melanin).
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