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Dermatopathology: Practical & Conceptual October - December 1996
Dysplastic Nevus:: National Institutes of Health Consensus Development Conferences, 1983 and 1992— Consensus?
Daniela Massi, MD
Timothy A. Nielsen, MD
A. Bernard Ackerman, MD
Key Questions Posed by the Organizers
“Dysplastic Nevus”: Clinical Aspects
“Dysplastic Nevus”: Histopathologic Aspects
“Dysplastic Nevus”: Cytologic Atypia
Prevalence of “Dysplastic Nevi”
“Dysplastic Nevus Syndrome”
Risk of Melanoma
Management of “Dysplastic Nevi”
"Dysplastic Nevus Syndrome"
1983 NIH Consensus Development Conference:
"The presence of multiple dysplastic nevi in two or more family members has been termed the "dysplastic nevus syndrome."
1992 NIH Consensus Development Conference:
"Some families are affected with an inherited familial atypical mole and melanoma (FAM-M) syndrome. This syndrome is defined by (1) occurrence of melanoma in one or more first-or second-degree relatives, (2) large numbers of moles (often . 50), some of which are atypical and often variable in size, and (3) moles that demonstrate certain distinct histological features."
In 1983, the Panel defined "dysplastic nevus syndrome" (DNS) as the presence of DN in two or more family members (no mention was made of a personal or familial history of melanoma), the same definition given earlier in 1983 by Kraemer et al. for familial DNS.
According to Greene et al., in 1980, familial DNS was defined as a person having a history of DN and/or melanoma.
This definition was different from that proposed earlier by Clark and co-workers
who characterized the B-K mole syndrome by the presence in a person of .10 to ,100 nevi, and from that in the same year by Elder et al. who deemed a single DN as sufficient to establish the syndrome.
If the definition of DNS set forth by the Panel of 1983 is accepted as correct, then the overwhelming majority of Caucasians qualify as having the DNS. But because the term "dysplasia" and DN have never been defined in a consistent, lucid fashion, meaningful definition of DNS by the Panel, or by anyone, is impossible.
The Panel of the Consensus Development Conference of 1992 proposed that DNS be renamed "FAM-M" (Familial Atypical Mole and Melanoma syndrome), a hybrid between what Lynch et al. in 1978 had described as FAMM-M
(Familial Atypical Multiple Mole and Melanoma syndrome) and what Kopf et al. in 1990 had called "atypical mole syndrome."
The definition of DNS offered by the Panel of 1992 was very different from the one proffered by the Panel of 1983. In 1992, a history of melanoma became mandatory for definition of FAM-M, and the number of DN required for that diagnosis changed from two or more to more than 50. Kopf et al.
averred that a person with "atypical mole syndrome" must have more than 100 moles, whereas Lynch et al. failed to specify the number of moles required for diagnosis of FAMM-M syndrome. Furthermore, Lynch et al. defined the syndrome in terms of two or more family members (usually from a modified nuclear pedigree, including offspring, siblings, parents, aunts, uncles, grandparents) with proven cutaneous melanoma.
As of 1992, it is obvious that the DNS had yet to be defined in a consistent, comprehensible way. It still has not, and never will be, because the assumptions on which it is based are flawed so seriously.
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