The "Ugly Duckling" Sign: An Early Melanoma Recognition Tool For Clinicians and the Public

Alon Scope, MD; Ashfaq A. Marghoob, MD


The Melanoma Letter. 2007;25(3):1-3. 

In This Article

Dermoscopic Proof

The premise underlying the ugly duckling sign is that the patient's "normal" moles resemble each other, like siblings.[7] We refer to this premise as "moles breed true." Our team tested this concept on dermoscopic images of nevi. The aim was to investigate whether physicians evaluating dermoscopic images would identify common patterns of nevi with in individual patients.[9] Images of 205 nevi from 18 patients were evaluated for global dermoscopic pattern. Indeed, 83 percent of patients harbored a dominant global dermoscopic pattern, defined as a pattern occurring in more than 40 percent of their nevi. Most of these patients had 1-2 additional minor patterns, defined as occurring in 20-39 percent of nevi. Thus, in most patients, 80 percent or more of their nevi could be grouped into one, two, or three patterns. Similarly, HofmannWellenhof, et al[10] examined 829 nevi on 23 individuals for global dermoscopic pattern. Fifty two percent of the patients displayed a dominant dermoscopic pattern in their nevi.


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