Cells of the skin and underlying tissue may accumulate and cause growths. Growths may be raised or flat and range in color from dark brown or black to skin-colored to red. They may be present at birth or develop later.
When the growth is controlled and the cells do not spread to other parts of the body, the skin growth (tumor) is noncancerous (benign). When the growth is uncontrolled, the tumor is cancerous (malignant), and the cells invade normal tissue and may even spread (metastasize) to other parts of the body.
Most skin growths are noncancerous. However, people should see a doctor to determine whether a growth is skin cancer. Noncancerous skin growths are often more of a cosmetic problem than anything else.
Causes
Doctors do not know what causes most noncancerous skin growths. Some growths, however, are known to be caused by
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Viruses (for example, warts)
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Systemic (bodywide) disease (for example, xanthelasmas or xanthomas caused by excess fats in the blood)
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Genetics (for example, seborrheic keratoses)
Diagnosis
Doctors are often able to recognize skin growths by examining the skin.
Some growths are removed and examined under a microscope. This procedure is called a biopsy. Other tests may be done depending on the growth.