The so-called dysplastic nevus is not dysplastic at all.

Editorial

In a recent two-part essay entitled “The dysplastic nevus: from historical perspective to management in the modern era” published in the Journal of American Academy of Dermatology, Duffy and Grossman concluded, following comprehensive literature review, historically, histologically, clinically and molecularly, that the so-called dysplastic nevus is a type of melanocytic nevus and should be managed like other types of melanocytic nevi [1,2]. This reinforces the notion set forth by the late Bernie Ackerman, who asserted more than two decades ago that the so-called dysplastic nevus is the commonest melanocytic nevus in man [3].

Duffy and Grossman acknowledged that the term dysplastic nevus is inappropriate, however, they did not advocate change of the term in these words: “the term ‘dysplastic nevus,’ despite its problems, should not be abandoned—it has become entrenched in our dermatologic language and practice.” [1] We believe the authors underestimated the ramification of continuing the use of an inappropriate term.

Historically, the introduction of the term dysplastic nevus was based on an assumption, which has been found to be incorrect. Clark and coworkers believed in the multistep carcinogenesis theory and thought that the lesion under discussion represented an intermediate step between nevus and melanoma. In an article by Clark and coworkers, they expressed this view in these words: “[dysplastic nevi] fit nicely into the schema of progression from hyperplasia to dysplasia to neoplasia that is accepted in many epithelial tumor systems, both experimental and human” [4]. As one examines the literature, there is really no evidence in support of the multistep carcinogenesis theory and there is no intermediate entity between nevus and melanoma [5].

Secondly, although the word “dysplasia” has never been lucidly defined in pathology, whenever the word dysplasia is used in tumor pathology, it generally refers to intraepithelial neoplasia with cytomorphologic features of malignancy, namely, carcinoma in situ lesions, by surgical pathologists. If one looks for an equivalent lesion to the so-called dysplastic (carcinoma in situ) lesions of epithelial tissue in melanocytic neoplasia, melanoma in situ would be the one, not the so-called dysplastic nevus.

We have come to know the lesion under discussion is as a variant of melanocytic nevus and the commonest nevus in humans. In other words, it is totally benign and not dysplastic at all, namely, neither an intermediate step between nevus and melanoma nor a carcinoma in situ equivalent. There is no need to excise it surgically unless other than for cosmetic reasons or suspicion of melanoma. However, such a benign lesion has certainly been over-treated since 1980, when the term dysplastic nevus was first introduced [4], due to the continued wrong belief that it represented an intermediate step between nevus and melanoma or a carcinoma in situ equivalent. A survey by Tripp et al found that 86% of dermatologists intend on biopsy to remove the so-called dysplastic nevus completely, 75% use margins of 2 mm or less, and 67% would re-excise the so-called dysplastic nevus with positive histologic margins [6]. Continued use of the term dysplastic nevus will certainly prolong the confusion and controversy of more than 30 years for many more years to come and contribute to the over-treatment of innumerable patients.

When a term does not reflect the true nature of a lesion and continues to cause confusion in the medical field and mismanagement of patients, then the term has to be changed. Simply stating that a term “has become entrenched in our dermatologic language and practice” does not preclude that term from being changed.

What should the lesion under discussion be called then? We propose to simply call it melanocytic nevus—that is what it truly is. Alternatively, one can call it Clark’s nevus, as the late Ackerman proposed, if one desires to distinguish it from other types of nevi [7]. Just do not call it dysplastic nevus any more, for the so-called dysplastic nevus is not dysplastic at all.