Early detection and prompt excision of malignant melanomas offer the best chance of cure. A series of visual criteria were developed more than a decade ago to help physicians identify early melanoma and guide its treatment. The asymmetry, border, color and dimension (ABCD) criteria represent a practical but imperfect system for evaluation of skin lesions. As with any clinical diagnosis, the evaluation of a lesion using the ABCD criteria is highly subjective. Bono and associates tested the validity of the ABCD criteria compared with that of telespectrophotometric measurements in identifying malignant melanomas.
All patients enrolled in the study had cutaneous pigmented lesions that required surgical biopsy for early diagnosis of melanoma. Mean patient age was 40 years, and approximately twice as many women as men were enrolled. Lesions were located primarily on the trunk (63 percent), followed by the extremities (32 percent) and the head (5 percent). Before surgical excision, all lesions were evaluated with telespectrophotometry for roundness, smoothness, mean reflection (color) and size, the same features that comprise the ABCD criteria.
A total of 186 patients with 195 lesions were enrolled in the study. Of these, 77 were believed to be malignant melanomas and 118 to be benign skin lesions, based on clinical diagnosis alone. Pathology revealed that 53 of the lesions were melanomas, and the rest were benign skin lesions. Of interest, six of the melanomas were less than 6 mm in diameter. Telespectrophotometric measurements, particularly mean reflectance (color) and size, more reliably identified melanomas than the ABCD criteria. Of these, color was the most sensitive predictor. Roundness and smoothness did not contribute significantly to the diagnosis. Telespectrophotometric measurements also reliably distinguished dysplastic nevi from melanomas.
The authors conclude that the ABCD criteria are a simple, useful means of identifying malignant melanomas. However, to be more effective as a diagnostic tool, the criteria should be modified to account for changes in the characteristics of lesions. Of the information provided by telespectrophotometric measurements, the most important variable in distinguishing melanoma from nevi appears to be color. In this study, the darker the skin lesion, the more likely that it was a melanoma. Therefore, the authors recommend that the C in ABCD should represent “color darkness,” as this distinction would increase the sensitivity of the ABCD criteria in identifying melanomas.