[Skip to Navigation]
June 2016

Large Acquired Nevus or Dysplastic Nevus: What’s in the Name of a Nevus?

Author Affiliations
  • 1Department of Dermatology, Medical University Graz, Graz, Austria
  • 2Dermatology Service, Memorial Sloan Kettering Cancer Center, New York, New York
JAMA Dermatol. 2016;152(6):623-624. doi:10.1001/jamadermatol.2015.6186

A name should convey the etiology, morphology, or biology of the disease entity in question.

In 1978, Clark et al1 described a melanoma-prone family with many nevi. The nevi in these family members were variable in size, shape, and color, and many of the nevi had relatively large diameters. In addition, the family members with such nevi were at increased risk of developing melanoma. To help differentiate these nevi from others, Clark et al1 coined the term B-K mole, which later became known as dysplastic nevus (DN).2 Although Clark et al1 did not consider DNs to be obligate precursors to melanoma, they hypothesized that DNs may represent an intermediate-stage lesion with a higher propensity for progression toward melanoma. It is understandable how the aforementioned observation and premise evolved in the minds of many physicians into 2 action items. First, by screening these individuals, one may find de novo melanomas early (which has been reported in various studies3,4). Second, by removing their DNs, one could potentially prevent the development of melanoma. At face value, this premise seemed logical, but, unfortunately, numerous studies3,5 have found that the removal of DNs cannot actually prevent the development of malignant melanoma because most develop de novo. In addition, although 30% of melanomas are histopathologically associated with a nevus, the most common associated nevus is a so-called common or congenital-type nevus.5 Because of the connotations associated with the word dysplastic, alternative names, such as atypical nevus, Clark nevus, and nevus with architectural atypia, had been proposed. However, renaming this nevus did not eradicate the underlying basic conceptual error that had permeated the minds of many physicians that these nevi were histologically and clinically dysplastic and atypical—and, as a consequence, premalignant. Although evidence is emerging that, on a molecular level, there is progressive accumulation of mutations from nevus to melanoma, this does not mean there are clinical or histopathologic features that can reliably identify an intermediate-stage lesion with a heightened risk of transforming into a malignant tumor.4 With the exception of congenital nevi, to our knowledge, no evidence has yet emerged identifying a clinically distinct subset of nevi bearing a higher risk of developing an associated melanoma or transforming into melanoma. Despite this evidence, DNs still cause concern among pathologists, other physicians, and even patients. Physicians often explain to patients that the biopsied nevus was a premelanoma, almost a melanoma, or on its way to becoming a melanoma. Because of this practice, both the physician and patient will often decide to reexcise these nevi to ensure complete removal.

Add or change institution