Squamous cell carcinoma. This type of skin cancer is not as dangerous as melanoma but may spread to other parts of the body if not treated. It grows over some months and appears on skin most often exposed to the sun. It can be a thickened, red, scaly spot that may bleed easily, crust or ulcerate.
Melanoma begins on the skin where it is easy to see and treat. However, it can grow into the skin, reaching the blood vessels and lymphatics, and can spread .