Observed change in a mole should be enough in itself to warrant investigation as a possible early melanoma, in addition to the established criteria of lesion asymmetry, border irregularity, non-uniform color, and diameter greater than 6 millimeters, according to an article in the December 8th issue of the Journal of the American Medical Association.

Almost 20 years ago, a group of American dermatologists introduced the ABCD acronym for recognizing growths on the skin that could be early melanomas. They devised the rule based on many years of clinical experience, which taught them that early melanomas can be identified by their asymmetry, uneven borders, colors, and size.

The ABCD rule has been helpful in identifying early melanoma. But now the original group who devised the rule, along with some of their younger colleagues, recommends expanding it to recognize that early melanomas frequently change in appearance. This is especially true for a type of melanoma called nodular that doesn’t fit neatly into the ABCD criteria, explained coauthor David Polsky, MD, PhD.

Nodular melanoma accounts for 10 to 15 percent of all melanomas. One of four basic types of melanomas, the nodular form is the most aggressive. But it frequently doesn’t look suspicious, noted Polsky, because it may not have the ABC features of early melanomas. However, there are many reports in the medical literature that highlight the changing nature of these lesions, the most important clue to their diagnosis.

In a study of 125 patients cited in the current article, 78 percent of patients with nodular melanoma noted some kind of a change in the appearance of their lesion. Patients with other forms of melanoma in the study also noted a change in the appearance of their lesion. Moreover, in another cited study of 169 pigmented lesions, dermatologists noted that the lesions that had changed were at least four times more likely to be melanoma than the lesions that did not change.

“An evolving lesion is one which is changing in terms of the five S’s - size, shape, symptoms such as itching or tenderness, surface bleeding, or shades of color,” said Polsky. “Essentially, a lesion that significantly changes is a concerning lesion.”

The incidence of melanoma continues to rise. This year it is expected to strike 55,100 people in the United States, and some 7,910 people with the disease are expected to die, according to the American Cancer Society. Excessive exposure to sunlight, a fair complexion, a family history of melanoma, and numerous moles, among other factors, place people at higher risk for developing the disease.