0.4 Integumentary system module 5: diseases, disorders, and  (Page 48/21)

The integumentary system is susceptible to a variety of diseases, disorders, and injuries. These range from annoying but benign (usually relatively harmless) bacterial or fungal infections that are categorized as disorders, to skin cancer and severe burns, which can be fatal. In this section, you will learn several of the most common skin conditions.

Diseases

One of the most talked about diseases is skin cancer. Cancer is a broad term that describes diseases caused by abnormal cells in the body dividing uncontrollably. Most cancers are identified by the organ or tissue in which the cancer originates. One common form of cancer is skin cancer. The Skin Cancer Foundation reports that one in five Americans will experience some type of skin cancer in their lifetime. The breakdown of the ozone layer in the atmosphere and the resulting increase in exposure to UV radiation has contributed to its rise. Overexposure to UV radiation damages DNA, which can lead to cancer. Although melanin offers some protection against DNA damage from the sun, often it is not enough. The fact that cancers can also occur on areas of the body that are normally not exposed to UV radiation suggests that there are additional factors that can lead to cancer of the skin.

In general, cancers result from an accumulation of DNA mutations. These mutations can result in cell populations that do not die when they should and uncontrolled cell growth that leads to tumors. Although many tumors are benign, some produce cells that can mobilize and establish tumors in other organs of the body; this process is referred to as metastasis    . Cancers are characterized by their ability to metastasize.

Basal cell carcinoma

Basal cell carcinoma is a form of cancer that affects the actively dividing stem cells in the stratum basale of the epidermis. It is the most common of all cancers that occur in the United States and is frequently found on the head, neck, arms, and back, which are areas that are most susceptible to long-term sun exposure. Although UV rays are the main culprit, exposure to other agents, such as radiation and arsenic, can also lead to this type of cancer. Wounds on the skin due to open sores, tattoos, burns, etc. may be also increase the chance of future cancers as well. Basal cell carcinomas start in the stratum basale and usually spread along this boundary. At some point, they begin to grow toward the surface and become an uneven patch, bump, growth, or scar on the skin surface ( [link] ). Like most cancers, basal cell carcinomas respond best to treatment when caught early. Treatment options include surgery, freezing or cryosurgery , and topical ointments (Mayo Clinic 2012).

Basal cell carcinoma