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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": Cytologic Atypia
1983 NIH Consensus Development Conference:
"Cytologic atypia with enlarged hyperchromatic melanocytic nuclei, often present but not essential for the diagnosis."
1992 NIH Consensus Development Conference:
"The essence of the problem in defining the significance of nevi with architectural disorder seems to rest in the degree of nuclear atypia in the lesion required for the histological diagnosis. At one end of the spectrum are nevi with architectural disorder described above, usually recognizable with the low-power or scanning microscope objective. Atypical melanocytes may be absent or scant and randomly scattered through the lesion. At the other end of the spectrum is a lesion with extensive and severe melanocytic atypia that may pose a difficult differential diagnosis from melanoma in situ."
There is no "spectrum" of nuclear changes in DN ranging from "absent" to "severe." For practical purposes, there is no nuclear atypia in DN; nuclei are small, oval, and monomorphous. By emphasizing "melanocytic atypia" in DN, the Panels of 1983 and 1992 paid lip service to the continuously repeated refrain of Clark and co-workers that melanocytic nuclear atypia was the sine qua non for diagnosis of DN.1719 By referring to atypical melanocytes "randomly scattered throughout the lesion," the panel of 1992 simply paraphrased the dictum of Clark et al. that "random cytologic atypia" was essential for diagnosis of DN. Only two statements by the Panels in regard to cytologic atypia are correct, to wit, cytologic atypia is "not essential for the diagnosis" of DN (1983) and "atypical melanocytes may be absent" from DN (1992). In actuality, they are absent.
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