1983 NIH Consensus Development Conference: "Among patients with dysplastic nevi, who constitute a heterogeneous group, the overall lifetime risk has been estimated at 10 percent. . . . Lifetime risk of melanoma may approach 100 percent for those people with dysplastic nevi who are from melanoma-prone families, i.e., families with two or more first-degree relatives having cutaneous melanomas."

1992 NIH Consensus Development Conference: "Persons with this syndrome have a markedly increased risk of developing melanoma. Their lifetime risk may be as high as 100%. . . . For those individuals having atypical moles without a family history of melanoma, the risk of developing a melanoma is clearly different from that in someone with FAM-M syndrome. The increased relative risk for an individual with nonfamilial atypical moles to develop melanoma compared with that of the general population may range from two to eight."

Critique: The Panels of the Consensus Development Conferences of 1983 and 1992 accepted, unconditionally, the legitimacy of the concept of a DNS, even though they themselves could not define it in a repeatable way.

Data concerning the relative risk of developing melanoma in patients bearing DN were substantially the same in the statements of 1983 and 1992, namely, 10% in the absence of a family history of melanoma and 100% in the presence of such a history. The only published data on risk of melanoma in patients with DN prior to the first Consensus Development Conference were those of Kraemer et al., also in 1983,²¹ who established "subtypes" of DNS according to risk of melanoma. According to our calculations, the only group of patients in their series with increased risk of melanoma in comparison with the general population was one with familial melanoma. Most studies published more recently have not demonstrated any correlation between "melanocytic dysplasia," as assessed histopathologically, and risk of melanoma. In addition, authors of many of those studies came to conclusions about presence of DNS based entirely on clinical assessment of DN, without verification of the diagnosis histopathologically, despite the fact that Clark et al., since 1978, had insisted that the sine qua non for diagnosis of DN was nuclear atypia of melanocytes. Parenthetically, the criteria on which clinical diagnosis of DN was based were baseless, i.e., variations on the theme of the ABCDs.