Thanks for this interesting summarizing piece. However, there are two issues that I believe need some adjustments. First, melanomas are not epithelial in origin. They arise from neuroectodermal cells and exhibit a different immunophenotype.
Secondly, the concept of dysplastic nevi is still controversial. Many, in fact at least 2/3of all melanomas arise de novo, i.e. without clinically evident precursor lesions; conversely, most clinically atypical nevi whose majority by inference will show histologic „dysplasia“ never turn into a melanoma. Acute UV exposure alone is sufficient to induce histologic „dysplasia“ in common nevi which illustrates the poor positive predictive value of dysplastic histologic features. Lastly, the criteria for differentiating severe melanocytic „dysplasia“ from early/thin melanoma are at least partially subjective. The illustrations above are a case in point: in the high magnification picture that is labeled „dysplastic nevus“ I personally would diagnose an established malignant melanoma.
There is also enlightening study regarding the association between melanocytic nevi and melanoma by Martin-Gorgojo et al. from 2018.
Thanks for your comment. Of course, melanocytes are not epithelial - we apologize for the mistake. But, melanocytes are surrounded by epithelial keratinocytes, which we believe causes some transforming melanocytes to have intraepithelial-like histology. We added that dysplastic nevi are controversial and the Martin-Gorgojo reference.
Thanks for this interesting summarizing piece. However, there are two issues that I believe need some adjustments. First, melanomas are not epithelial in origin. They arise from neuroectodermal cells and exhibit a different immunophenotype.
Secondly, the concept of dysplastic nevi is still controversial. Many, in fact at least 2/3of all melanomas arise de novo, i.e. without clinically evident precursor lesions; conversely, most clinically atypical nevi whose majority by inference will show histologic „dysplasia“ never turn into a melanoma. Acute UV exposure alone is sufficient to induce histologic „dysplasia“ in common nevi which illustrates the poor positive predictive value of dysplastic histologic features. Lastly, the criteria for differentiating severe melanocytic „dysplasia“ from early/thin melanoma are at least partially subjective. The illustrations above are a case in point: in the high magnification picture that is labeled „dysplastic nevus“ I personally would diagnose an established malignant melanoma.
There is also enlightening study regarding the association between melanocytic nevi and melanoma by Martin-Gorgojo et al. from 2018.
Thanks for your comment. Of course, melanocytes are not epithelial - we apologize for the mistake. But, melanocytes are surrounded by epithelial keratinocytes, which we believe causes some transforming melanocytes to have intraepithelial-like histology. We added that dysplastic nevi are controversial and the Martin-Gorgojo reference.