Most importantly, because melanoma is highly preventable, it s critical for nurses to understand how to educate patients about how to take everyday measures to prevent its occurrence. To understand melanoma, it s helpful to briefly review the components of skin the body s largest organ. Skin is composed of two layers, the outermost epidermis and the inner dermis. The epidermis is made up of flat, scalelike cells called squamous cells, with the round, basal cells lying beneath them. Below the basal cells in the lowest part of the epidermis are cells known as melanocytes that produce melanin, the pigment that gives skin its color.
Melanin protects deeper skin layers from the sun s harmful effects.
The second skin layer, the dermis, contains blood and lymph vessels, hair follicles and sweat and oil glands. While skin cancer can develop from squamous and basal cells, the most dangerous skin cancer, melanoma, forms from melanocytes that have become malignant. Most melanoma occurs in the skin, but it also may develop in other tissues that contain melanocytes, such as the eyes and digestive tract. This article will discuss only melanoma of the skin. Melanoma can originate anywhere on the skin, but is found most often on the legs among women and on the trunk, head and neck in men.