Dysplastic naevi: the controversy continues
- The entity ‘mildly dysplastic naevus’ has been removed from the World Health Organisation’s classification of dysplastic naevi.
- Dysplastic naevi are now to be graded as ‘low grade dysplastic naevus’ (previous moderately dysplastic naevus) or ‘high grade dysplastic naevus’ (previous severely dysplastic naevus).
- Current data suggest no further treatment is necessary for lentiginous junctional/compound naevi and dysplastic naevus with low grade dysplasia (previous mildly dysplastic and moderately dysplastic naevi) with clear histologic margins and no pigment evident clinically, unless there was a high level of prebiopsy clinical concern.
- Re-excision with a 2-5mm clinical clearance is recommended for high grade dysplastic naevi (previous severely dysplastic naevi) with involved histologic margins.
- There is growing evidence that observation may be reasonable for low grade dysplastic naevi (previous moderately dysplastic naevus) if they were excised with clinically clear margins/ no residual clinical pigment is observed, despite histologically involved margins. More data may be required before this is accepted into clinical practice.
- There does not appear to be a clear consensus regarding whether high grade dysplastic (previous severely dysplastic) naevi require re-excision, if initially excised with clear margins, albeit less than 2mm.
Dysplastic naevus: the controversy since the 1970s
The entity of dysplastic naevus has been shrouded in controversy since first described in the 1970s.1 This appears to be due to:
- Interobserver differences between histopathologists in applying the previous three tier grading system for dysplasia
- Perceived risk of progression to melanoma, and
- The possibility of benign entities simulating melanoma, all of which contribute to uncertainty and variability in management.2, 3
Dysplastic naevi are benign neoplasms of melanocytes.3
Dysplasia in melanocytes may occur de novo or in association with either ...