WAIKOLOA, HAWAII — The “ugly duckling” sign showed impressive sensitivity for melanoma when applied by physicians as well as nonmedically trained individuals for rating melanocytic lesions, according to Dr. Ashfaq A. Marghoob.
The results of this study suggest the ugly duckling sign may be a valuable melanoma screening tool readily teachable to primary care physicians, nurse practitioners, and patients performing periodic skin self-examination, Dr. Marghoob reported at the annual Hawaii dermatology seminar sponsored by Skin Disease Education Foundation.
The ugly duckling sign was first described in 1998 by Dr. Jean-Jacques Grob of the Hôpital Sainte Marguerite, Marseille, France. It holds that nevi on a given individual tend to resemble each other. The ugly duckling—the outlier, the exceptional nevus, the one that looks different from the others—is more likely to be a melanoma, even if it does not exhibit the classic features ascribed to melanoma in the longstanding ABCD [assymetry, border, color, and diameter] rule.
The ABCD rule, launched in 1985, is a form of gross clinical analysis that “has served us well” in the early recognition of melanoma, said Dr. Marghoob, a dermatologist at Memorial Sloan-Kettering Cancer Center, New York. But it has shortcomings: There is morphologic overlap with dysplastic nevi, resulting in many unnecessary excisions, and ABCD criterion does not fit for many thin melanomas.
To test the utility of the ugly duckling sign when applied by a diverse group of people, Dr. Marghoob and his coinvestigators assembled a portfolio of digital photographs of the backs of 12 patients at high risk for melanoma. Each of the patients had at least eight dysplastic nevi on the back. In five patients, one of the skin lesions was a melanoma, which was removed and histologically confirmed after the pictures were taken. The photo spread included whole-back overview images as well as clinical close-ups of a total of 145 lesions.
The lesion raters consisted of 13 general dermatologists, 8 dermatologists with special expertise in pigmented lesions, 5 nurses, and 8 secretaries and other nonclinical hospital staff. They were asked if any of the 145 nevi differed from the others on the patients' backs.
There was excellent agreement on the ugly duckling sign among observers. All five melanomas but only 3 of 140 benign nevi were identified as ugly duckling lesions by at least two-thirds of the raters. The sensitivity of the ugly duckling sign—that is, the percentage of melanomas identified as “different”—was 100% for the experts, 89% for the general dermatologists, 88% for the nurses, and 85% for the nonclinicians. For the overall group, the sensitivity of the ugly duckling sign was 90% (Arch. Dermatol. 2008;144:58–64).
That 85% sensitivity when the ugly duckling sign was applied by nonclinicians is much higher than the percentage seen in studies of the ABCD method, Dr. Marghoob observed. “Could this be a new public health message? “[Something] along the lines of, 'Look for the ABCD features, but if you see a lesion that looks [different from] the surrounding lesions on your skin—even if it doesn't have the ABCDs—see a dermatologist.'”
He noted that the overall melanoma survival rate in the United States has soared from less than 60% in 1970 to greater than 90% in 2008, mainly as a result of improved detection of early disease, since there are still no effective systemic therapies for advanced melanoma.
In 1965, only about 60% of melanomas were diagnosed when localized to the skin, compared with more than 80% today. And although only about 35% of melanomas were less than 1 mm thick at diagnosis in 1976–1980, by 2000 that figure had climbed to 60%.
Widespread adoption of the ugly duckling sign could help improve early diagnosis of melanoma. Total body photography, dermoscopy, confocal microscopy, and short-term mole monitoring via a stepped-up schedule of office visits in selected patients are additional tools likely to lead to further improvements, he said.
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If a lesion looks different fromthe surrounding lesions—even if it doesn't have the ABCDs—see a dermatologist. DR. MARGHOOB