National Institutes of Health Consensus Conference

 
"Clinical features of de novo pigmented lesions suggestive of melanoma include Asymmetry, Border irregularity, Color variegation, and Diameter greater than 6 mm (the ABCD's of melanoma). An asymmetric lesion is one that is not regularly round or oval. Border irregularity refers to notching, scalloping, or poorly defined lesion margins. Color variegation refers to a lesion with shades of brown, tan, red, white, or blue/black, or combinations thereof. Although a high level of suspicion exists for a lesion greater than 6 mm in diameter, early melanomas may be diagnosed at a smaller size. Earliest lesions are flat or macular and may have altered skin markings. However, a palpable lesion with uniform or irregular surface features or benign-appearing pigmented and nonpigmented lesions that change rapidly can represent early melanoma."
 
National Institutes of Health Consensus Conference: Diagnosis and Treatment of Early Melanoma. JAMA 1992;268:1314–19.
 

Brief critique

 
Even the panel of the Consensus Development Panel that convened at the National Institutes of Health became captivated by the trite ABCDs. Curiously, the definition offered by the National Institutes of Health for "an asymmetrical lesion" as "one that is not regularly round or oval," hardly suffices and is incorrect. In regard to color variegation, the panel parroted shades of red, white, and blue, which are seen rarely in melanoma. To the credit of the panel was the acknowledgement that all melanomas begin smaller than "6 mm in diameter." Also commendable is the clear statement that "earliest lesions are flat . . ." When macular, which is synonymous with flat, melanomas do not have altered skin markings. That change appears only when melanomas no longer are in situ and neoplastic melanocytes of it are present in number in the papillary dermis, thereby obliterating the undulate pattern between rete ridges and dermal papillae.