During the course of a full skin examination, a 57-year-old white woman with a history of dysplastic nevus syndrome and basal cell carcinoma was found to have a distinct pigmented lesion on her chest.
The lesion, which occurred on a background of sun damage and lentigines, was noted to be asymmetric, possess irregular borders, demonstrate multiple colors, and extend well over 6 mm in greatest diameter (ABCD sign). The lesion was unlike any other on the patient’s skin surface (ugly duckling sign).
Shore RN, Skae AK. An Unusual Pigmented Lesion: What Is Your Diagnosis?. JAMA Dermatol. 2013;149(12):1376. doi:10.1001/jamadermatol.2013.4312