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

The Generally Apparent Outlier

However, for the ugly duckling to be a useful screening method, a melanoma would have to be apparent as an outlier, perceived by different observers as distinct from the patient's other moles. To this end, we studied whether the ugly duckling is generally apparent to different observers.[11] We showed participants[12] clinical overview images of the backs of patients with multiple atypical moles. Five of the images also displayed a MM on the back. The images were evaluated by 34 participants who ranged in expertise from pigmented lesion experts to non-clinical staff members (e.g., research engineers). A generally apparent ugly duckling was defined as a lesion perceived as different by at least two thirds of the participants.

Remarkably, in this virtual setting, all five MMs and only three of 140 other nevi (2.1 percent) were generally apparent as different to the observers. The sensitivity of the ugly duckling sign for MM detection was 0.9 for the whole group of participants, and as high as 0.85 for the non-clinicians. These relatively high sensitivity values for the ugly duckling sign suggest that it should be further assessed in the setting of MM screening by primary health care providers and even for patient self-examination.


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