Skin Cancer

Skin Cancer

Skin cancers originating from epithelial cells are called cutaneous carcinomas (squamous cell carcinomas or basal cell carcinomas), whereas those arising from melanocytes are cutaneous melanomas (melanocar-cinomas or malignant melanomas). The UV rays of the sun can cause skin cancer, usually on the head and neck because they are the areas most exposed. Fair-skinned people and elderly people are the most likely candidates for skin cancer. The use of sunscreen or sunblock of minimum SPF-15 may protect against sunburn (including UVA and UVB rays), but not ­completely against skin cancer. Genetic factors and hormones may influence a person’s chance for devel-oping skin cancer. Although very common, skin can-cer is one of the easiest forms of cancer to diagnose and treat. When detected and treated early, survival rates are high. The three types of skin cancer, named for the specific epidermal­ cells in which they originate, are:

■■ Basal cell carcinoma: The most common yet least dangerous type, it begins in the stratum basale, invading the dermis. A small, shiny lesion appears as a “bump” on the skin, which enlarges to form a central depression with a beaded, pearl like edge (FIGURE 6-9).

■■ Squamous cell carcinoma: It begins in the keratino-cytes of the stratum spinosum; the lesion appears raised, reddened, and scaly, forming a concave ulcer with edges that are raised (FIGURE 6-10).

Early detection and surgical removal raises the survival rate, but this cancer often metastasizes to the lymph nodes to become potentially fatal.

■■ Malignant melanoma: This much more serious form of skin cancer is increasing in incidence. It often starts in the melanocytes of a preexisting mole, metastasizing quickly. It is often fatal if not treated immediately. The lesion appears as a large, flat, dark-colored patch that spreads and has a “scalloped” border (FIGURE 6-11). According to the American Cancer Society, the ABCD Rule should be used for recognizing melanoma:

·           Asymmetry: The two sides of a mole or pig-mented spot do not match

·           Border irregularity: The lesion’s borders have indentations

·           Color: There are several colors in the pig-mented spot, such as black, brown, tan, and occasionally blue or red

·           Diameter: The lesion is larger than a pencil eraser (approximately 6 mm in diameter)

1. What type of skin cancer is the most malignant?

2. What is the rule used for recognizing melanoma?