Basal cell and squamous cell carcinomas are the two most common and most curable skin cancer. Symptoms as a sore, mole, or other lesion that does not heal and changes in shape, color, size, or thickness, a persistent skin lesion or sore that is painful or itchy; it may form an ulcer, bleed, scab over, heal, and then recur.
Basal cell carcinomas start in cells in the lower layers of the epidermis (the outer skin); more than 80% are on the head and neck.
Squamous cell carcinomas develop in the cells just under the skin's protective outer (horny) layer of dead cell; about 75% are on the head and face, 15% are on the hands.
If left untreated, 3-10% spread to nearby tissues, such as regional lymph nodes, underlying nerves, or distant organs, including the liver, lung, and brain.
This type of skin cancer can be very painful if it engulfs an underlying nerve, especially the facial trigeminal nerve.