Not all growths on the skin are skin cancer. And not all skin
cancers look alike. Pictured below are examples of basal cell and
squamous cell carcinoma—together called nonmelanoma skin cancers.
But keep in mind there's tremendous variability, even within each
type of skin cancer. A nonmelanoma skin cancer can be smooth or
crusty or even-colored or pigmented, and the borders may or may
not be well defined. You should have a dermatologist look at
anything that persists for three or more weeks (or seems to go
away then comes back) or bleeds easily.
Melanoma, also pictured below, is different in that most arise
from an existing mole. But as a melanoma grows, it causes changes
that distinguish it from a mole. The warning signs, sometimes
referred to as the ABCDs of melanoma, are: Asymmetry (one half
doesn't match the other half); Border irregularity (the edges are
ragged); Color variability (the pigmentation is uneven, with
various colors present); and Diameter (larger than a pencil
eraser, or about one-quarter inch across). Some experts have
urged that a fifth letter be added: E, for evolving. The idea is
that early melanomas often change in appearance, so be on the
lookout for changes in size, shape, bleeding, color, and symptoms
such as itching or soreness.
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