سرطان الجلد

أسباب

Cancer occurs when cells in the body divide without control or order. Eventually these uncontrolled cells form a growth or tumor. The term cancer refers to malignant growths. These growths invade nearby tissues and spread to other parts of the body. It is not clear exactly what causes these problems in the cells but is probably a combination of genetics and environment.

عوامل الخطر

The most common risk factor for melanoma is exposure to ultraviolet radiation. The most common source of this radiation comes form the sun but it is also found in sun lamps and tanning booths.

Melanoma is found most often in older adults but it can happen in young adults. Other factors that increase the risk of melanoma include:

• Certain types of moles called dysplastic nevi, or atypical moles
• Large nevi present at birth
• Fair skin, freckling
• Red or blonde hair
• Light-colored eyes
• Caucasian race
• Family members with melanoma
• Excessive skin exposure to the sun without protective clothing or sunscreen
• Suppressed immune system

الأعراض

Melanomas are not usually painful. They often have no symptoms at first.

The first sign is often a change in the size, shape, color, or feel of an existing mole. Melanoma may also appear as a new, dark, discolored, or abnormal mole. Remember that most people have moles. Almost all moles are benign.

The following are signs that a mole may be a melanoma:

• Uneven shape—one half does not match the shape of the other half
• Ragged edges—ragged, notched, blurred, or irregular; pigment may spread into surrounding skin
• Uneven color—color is uneven with shades of black, brown, or tan, and possibly even white, gray, pink, red, or blue
• Change—usually growing larger, changing shape, changing color, or changing texture
• Large size—usually larger than the eraser of a pencil (5 millimeters or ¼ inch)