From the Guidelines
The percentage of severely dysplastic nevi that progress to melanoma is estimated to be relatively low, likely less than 5%. Severely dysplastic nevi represent a point on the spectrum between benign nevi and melanoma, showing significant cellular atypia and architectural disorder. While these lesions are considered precursors to melanoma and indicate increased risk, the majority do not transform into malignancy. According to a study by Kmetz et al. 1, patients with biopsy-proven atypical nevi who were followed up for 5 years or longer showed no occurrence of melanoma, even when nearly half had involved biopsy margins. Another study evaluated 195 dysplastic nevi with mild to moderate atypia with a 2-year follow-up, reporting a 3.6% local recurrence rate, but no progression to melanoma 1.
Key points to consider in managing severely dysplastic nevi include:
- Complete excision with narrow margins (2-5 mm) to ensure complete removal and allow for comprehensive histological examination
- Regular monitoring with full-body skin examinations, typically every 3-6 months initially, then annually if no new concerning lesions develop
- Assessment of risk factors that may increase the likelihood of progression, such as genetic predisposition, personal or family history of melanoma, multiple dysplastic nevi, and excessive UV exposure. Patients with severely dysplastic nevi have a higher overall risk of developing melanoma elsewhere on their body, making regular monitoring crucial 1.
From the Research
Dysplastic Nevi and Melanoma Risk
- The exact percentage of severely dysplastic nevi that progress to melanoma is not explicitly stated in the provided studies.
- However, a study from 1990 2 estimates that patients with dysplastic nevi have at least a 6 percent lifetime risk of melanoma, and this risk may exceed 50 percent in severely affected patients with a family history of dysplastic nevi and more than one melanoma.
- Another study from 2012 3 suggests that dysplastic nevi confer substantial risk for melanoma, but does not provide a specific percentage of progression from dysplastic nevi to melanoma.
- A study from 2009 4 mentions that dysplastic nevi are associated with a higher risk of developing melanoma, but also notes that there is disagreement regarding the clinical management of dysplastic nevi and the histologic definition of dysplastic nevi.
Management and Surveillance of Dysplastic Nevi
- A survey of fellows of the American Academy of Dermatology in 2002 5 found that 75% of respondents perform follow-up total cutaneous examinations on all their patients with dysplastic nevi, and another 22% on some of them.
- The same study found that 86% of respondents usually intend to do total removals when they perform biopsies of dysplastic nevi, and 75% use margins of 2 mm or less when removing dysplastic nevi.
- A study from 2012 3 recommends preventative measures, such as sun protection and careful surveillance and biopsies of suspicious lesions as needed, for patients with dysplastic nevi.
Detection and Diagnosis of Melanoma
- A study from 2024 6 found that the combination of total body photography, digital dermoscopy, and reflectance confocal microscopy can allow early detection of melanoma in patients with a high risk for melanoma.
- The same study found that the use of reflectance confocal microscopy reduced the number needed to treat for melanocytic lesions, and led to the detection of more melanomas in comparison to dermoscopy alone.