Last Updated: 2008-01-21 16:00:08 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Identifying pigmented lesions that look different from a patient’s other moles – the "ugly duckling sign" – is a practical strategy when screening for malignant melanoma, according to a report in the Archives of Dermatology for January.

The ugly ducking model is based on the observation that "nevi in the same individual tend to resemble one another and that malignant melanoma often deviates from the individual’s nevus pattern," even in patients with multiple atypical nevi, Dr. Ashfaq A. Marghoob, of Memorial Sloan-Kettering Cancer Center in New York, and associates explain.

Dr. Marghoob’s group studied the ability of 34 individuals with varying levels of expertise to identify ugly duckling lesions in patients with multiple atypical nevi. The participants were 8 pigmented lesion experts, 13 general dermatologists, 5 dermatology nurses, and 8 nonclinical medical staff members.

The observers were presented with overview photographs of the back, as well as close-up images of individual lesions, from 12 patients who each had at least 8 atypical moles. There were a total of 145 pigmented lesions, among which five were malignant melanomas and 140 were benign.

All 5 melanomas and 3 benign lesions were perceived as different by at least two thirds of the participants, Dr. Marghoob and his associates report.

"Identification of the ugly duckling showed good sensitivity (0.85), specificity (0.83) and diagnostic accuracy (0.87) for the detection of malignant melanoma, even among nonclinicians," the authors write. The diagnostic accuracy was 0.96 for the experts, 0.91 for the general dermatologists, and 0.87 for the nurses and office staff.

"The usefulness of this method in malignant melanoma screening by primary health care providers and for patient self-examination should be further assessed," the investigators conclude.

Arch Dermatol 2008;144:58-64.

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