Carcinoma, cancer that begins in the skin or tissues that line or cover internal organs, can strike throughout the body. Basal cell carcinoma--the most common cancer in the world, according to The Skin Cancer Foundation--occurs most often on parts of the body routinely exposed to the sun like the face, ears, neck, scalp, shoulders and back. Causes of carcinoma vary depending on the affected body.
Ultraviolet light can cause skin cancer, or carcinoma, and wrinkling. Physicians recommend avoiding light from the sun and tanning beds, instead endorsing sunless self-tanning products and the use of broad-spectrum, water-resistant sunscreen with a sun protection factor, or SPF, of 30 or more on all exposed skin. Those who are exposed to ultraviolet light from the sun or tanning beds should carefully check over skin for growths or changes that may indicate a carcinoma.
Therapeutic radiation in the form of X-rays and psoralen plus ultraviolet A, or PUVA, treatments may cause squamous cell carcinoma and melanoma, both skin cancers. Whether therapeutic radiation patients are more apt to develop carcinoma depends on various factors including skin pigmentation, the dose of radiation received and medical status. Carcinomas caused by this type of radiation may develop over decades and may stem from childhood treatments.
A weakened immune system increases the risk of contracting carcinomas, making immunosuppressant drugs a factor in the cause of some skin cancers. According to MayoClinic.com, up to 80 percent of organ transplant patients taking medications to stop organ rejection develop squamous cell carcinoma sometime over the course of their lives. Heart transplant patients show the most risk due to the need to take higher dosages of organ rejection medications. Infection by the human papillomavirus, or HPV, may also cause carcinoma, both from the immunosuppressant drugs and the virus itself.