There is no single disease of skin cancer.
Look for the following terms
1 Malignant Melanona
2 Squamous Cell Carcinoma
3 Basal Cell Carcinoma
4 Cutaneous Lymphoma
also looks up Von Recklinhousen's disease or neurofibromatosis, stricktly not a cancer but just as disfiguring.
With the exception of neurofibromatosis, the above are generally confined to discrete areas.
Excision for Melanoma in the UK can be extensive and require skin flaps or grafts.Generally a good sized portion of normal tissue is removed, especially in the line of lymphatic drainage in order to make sure that as much nasty as possible is removed.