Basal cell carcinoma (BCC), or rodent ulcer, on a 59 year old female patient's arm. This is the most common form of skin cancer among fair-skinned people. It mostly affects the elderly, although in recent years the average age of onset has steadily decreased. It usually appears on the face and is thought to be caused by the ultraviolet radiation in sunlight. It slowly destroys surrounding tissue, but seldom spreads to other parts of the body. Treatments for basal cell carcinoma include radiotherapy, cryotherapy, cauterisation and surgical excision.