These lesions develop when short-wave UV-B radiation does not penetrate deeply in the skin, but rather, damages the outer cell layer of the epidermis, the squamous epithelium.
Squamous cell carcinomas can develop from scars or long-lasting inflamed wounds. In the buccal cavity (inner mouth region), toxins from alcohol and tobacco often contribute to the development of these lesions.
In addition to UV-B radiation exposure, individuals with weak immune systems (e.g. AIDS) or those experiencing immunosuppression (e.g. organ transplantation) are at risk for this type of non-melanoma skin cancer. “Moon child” disease (Xeroderma pigmentosa) is a possible genetic cause for developing squamous cell carcinoma.
- Squamous cell carcinoma is the second most common malignant skin cancer, making up 22% of all skin cancer cases.
- Metastasis can be spread through blood or lymph vessels; however, this is seen in only about 5% of cases.
- 80% of these tumors appear in the “sun terraces” (bald head, face, nose bridge, cheeks, ears, neck).
- Men are more frequently affected than women.
- Men between 70 and 74 years and women between 75 and 79 years of age are most frequently affected by SCC.
Two different skin disorders may precede mature squamous cell carcinoma formation: Actinic Keratosis and Bowen’s Disease.
In Actinic Keratosis, only a reddish and scaly spot is seen. The growth of the tumor begins with this spot and expands gradually into the surrounding tissue.
These tumors easily damage and bleed. Therefore, blood scabs often appear and cover the lesions.
Doctors can easily recognize these tumors. However, further studies must be completed to define the expansion of the tumor. Some possible tests to determine lesion characteristics include lymphatic drainage area studies and lymph node sonography. Eventually, X-ray, CT and MRI studies may be done.