Skin conditions. Sunburns, excessive tanning, radiation treatment, scarred areas, and organ transplants are some but not all of the conditions that may lead to skin cancer developent.
Sun damage. Repeated sun exposure can lead to skin cancer in susceptible people. Skin diseases do not lead internal cancer but some skin conditions can be associated with a cancer. In late stage cancers they can spread to the skin, and occasionally certain cancers can cause itching.