Skin Cancer Home > Malignant Melanoma
Each year, more than 53,600 people are diagnosed with malignant melanoma. The disease generally starts in the skin, but it can also develop in the eye or in other parts of the body where pigment cells are found. Symptoms include a mole that changes in size or color, or one that has irregular edges. Surgery is the most common method used to treat the condition.
What Is Malignant Melanoma?
Malignant melanoma is the most serious type of cancer of the skin. Each year in the United States, more than 53,600 people learn that they have this disease. In some parts of the world, especially among Western countries, malignant melanoma is becoming more common every year. In the United States, for example, the percentage of people who develop the disease has more than doubled in the past 30 years.
Malignant melanoma is one of the most serious types of skin cancer, because advanced malignant melanomas have the ability to spread to other parts of the body. When malignant melanoma starts in the skin, the disease is called cutaneous malignant melanoma. It can also develop in the eye (called intraocular malignant melanoma) or in other parts of the body where pigment cells are found. In rare cases, malignant melanoma may arise in the meninges, the digestive tract, lymph nodes, or other areas where melanocytes are found. Malignant melanomas that begin in areas other than the skin are not discussed in this article.
Understanding the Skin
The skin is the body's largest organ. The skin:
- Protects against heat, sunlight, injury, and infection
- Helps control body temperature
- Stores water, fat, and vitamin D.
The skin has several layers, but the two main layers are the epidermis (upper or outer layer) and the dermis (lower or inner layer).
Skin cancer begins in the epidermis, which is made up of three kinds of cells:
- Basal cells: Round cells under the squamous cells
- Squamous cells: Thin, flat cells that form the top layer of the epidermis
- Melanocytes: Found in the lower part of the epidermis, these cells make melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes make more pigment, causing the skin to tan, or darken.