The border is usually irregular and they often bleed. These lesions grow slowly and usually do not spread to other parts of the body. Basal Cell cancers appear as pearly or waxy nodules with central depressions or ulceration. This type of cancer grows slowly and only by direct extension. Malignant Melanoma is by far the most dangerous.
Melanomas often start as small, mole-like growths that increase in size and change in color.
The American Cancer Society offers a simple ABCD rule to outline the warning signals of melanoma. A is for asymmetry . One half of the mole does not match the other half. B is for border irregularity . The edges are ragged, notched, or blurred.