Cliff Rosendahl, Simon Clark, Syril Keena T. Que, Denis Moir, Harald Kittler, Jane M. Grant-Kels
ABSTRACT
The term ‘dysplastic naevus’ first introduced in 1980, has since engendered considerable debate regarding its ontological legitimacy, the appropriateness of its nomenclature, and its potential prognostic significance. In this review, we undertake a critical examination of the extant literature, including a focus on the past decade. We will present case-based evidence elucidating how the persisting misdiagnosis of certain melanoma foci as dysplastic naevus, an interpretive approach adopted by many pathologists since 1980, has perpetuated the misconception that dysplastic naevi serve as definitive precursors to melanoma. We will also attempt to explain the persisting popularity of the diagnosis. We assert, based on current knowledge as detailed and explored in this review, that irrespective of whether it exists as a histological entity, and regardless of its persistence in practice, a diagnosis of dysplastic naevus by pathologists has no clinical relevance and that it does harm, by unnecessarily complicating the therapeutic decision-making role of clinicians.
Summary
- Why was the study undertaken? – Since 1980, the entity ‘dysplastic naevus’ has been frequently reported by dermatopathologists with the commonly communicated assumption that it is an intermediate lesion between naevus and melanoma. In the last 10 years, there have been significant advances in knowledge which refute this implication. Despite this, genomic research into its status continues, as does its influence on patient management.
- What does this study add? – Diagnostic accuracy in reporting subtypes of melanocytic lesions has been shown to be neither reliable nor reproducible. Regardless of this, it is now known that a melanoma-associated naevus is just as likely to be non-dysplastic as dysplastic. Multiple studies have shown that the most common melanoma-associated naevus is the bland (non-dysplastic) dermal naevus. The diagnosis of ‘dysplastic naevus’ is not relevant with respect to prognosis, the relevant prognostic factor being naevus-count (any naevus type).
- What are the implications of this study for disease understanding and/or clinical care? – Because there is ongoing uncertainty and confusion regarding best management of various grades of naevus-dysplasia, the diagnosis of ‘dysplastic naevus’ can unnecessarily complicate therapeutic decision-making for a large proportion of naevi. We present a diagnostic alternative of ‘borderline melanocytic lesion’ where any diagnostic uncertainty is clearly reported, and we demonstrate how this can halve the proportion of equivocal diagnoses and clarify therapeutic decision-making.
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