Squamous cell carcinoma is the second most common form of skin cancer. It may present as a thickened red scaly spot at areas most often exposed to the sun.
It may sometimes spread to other parts of the body, so it is more dangerous than basal cell carcinoma, but spread is uncommon and it can usually be removed surgically without further problems.
Squamous cell carcinoma may arise from common spiny lesions on the sun-exposed skin of the elderly, called actinic keratoses.
In the case of squamous cell carcinoma, it is the accumulated damage of a life-time of sun exposure that is most important. In fact, squamous cell carcinoma is more common in outdoor workers like fishermen, farmers, and stone-masons, than in people who have an indoor job.
The non-melanoma skin cancers basal and squamous cell carcinoma are not usually fatal, but their surgical treatment can result in scars.