Melanoma is a disease in which malignant (cancer) cells form in the skin cells called melanocytes (cells that color the skin).
Melanocytes are found throughout the lower part of the epidermis. They 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.
The skin is the body’s largest organ. It protects against heat, sunlight, injury, and infection. The skin has 2 main layers: the epidermis (upper or outer layer) and the dermis (lower or inner layer).
When melanoma starts in the skin, the disease is called cutaneous melanoma.
There are 3 types of skin cancer:
- Basal cell skin cancer
- Squamous cell skin cancer.
Recurrent melanoma is cancer that has recurred (come back) after it has been treated. The cancer may come back in the original site or in other parts of the body, such as the lungs or liver.