What is Skin Cancer?
Skin cancer is the most common type of cancer in this country, with approximately one million Americans developing it each year. Skin cells, the building blocks that make up the skin, mature and die daily and new skin cells are formed to take their place when healthy skin cells grow and divide.
But when this orderly process goes wrong, new cells form before the skin needs them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor.
Through examination and biopsy, growths or tumors can be diagnosed as either benign or malignant:
Benign growths are not cancer:
- Benign growths are rarely life-threatening.
- Generally, benign growths can be removed. They usually do not grow back.
- Cells from benign growths do not invade the tissues around them.
- Cells from benign growths do not spread to other parts of the body.
Malignant growths are cancer:
- Malignant growths are generally more serious than benign growths.
- They may be life-threatening. However, the two most common types of skin cancer cause only about one out of every thousand deaths from cancer.
- Malignant growths often can be removed. But sometimes they grow back.
- Cells from malignant growths can invade and damage nearby tissues and organs.
- Cells from some malignant growths can spread to other parts of the body. The spread of cancer is called metastasis.
How Does Skin Cancer Differ from Melanoma?
Melanoma is only one type of skin cancer. There are several types of skin cancer, and each is named for the location in the skin where cancer forms:
The most common type of skin cancer, basal cell carcinoma is also the most treatable, especially if found early. This slow-growing cancer rarely spreads (metastasizes) to other parts of the body. It tends to appear as a skin-colored or reddish bump on the head, neck or hands that bleeds and scabs over repeatedly.
The second most common skin cancer, squamous cell carcinoma grows faster than basal cell carcinoma, although it is also highly treatable when detected early. Squamous cell carcinoma is typically found on the rim of the ear, face, lips and mouth. While unusual, it can spread to other parts of the body. It also tends to be skin-colored or red, and bleeds and scabs over repeatedly.
The least common but most serious type of skin cancer, melanoma, begins in pigment-producing cells called melanocytes, which give the skin its color. It is also called malignant melanoma, because it can spread to other organs. Melanoma may begin as a change in a mole or birthmark, or arise as a new mole-like growth. Rarely, melanomas can form in parts of the body not covered by skin such as the eyes, mouth, vagina, large intestine, and other internal organs.
The least common types of skin cancers include Merkel cell carcinoma, clear cell carcinomas and sebaceous carcinomas. These behave like melanoma, but arise from other parts of the skin such as the sensory corpuscles and oil glands.