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Therapeutic Approach

Dysplastic nevi (sometimes referred to as atypical nevi, large acquired nevi, or Clark nevi) are common, benign skin lesions composed of melanocytes. Although the terms “atypical nevus” and “dysplastic nevus” are often used interchangeably, “dysplastic nevus” is most appropriately used as a histologic diagnosis and “atypical nevus” as a clinical diagnosis.

The clinical diagnosis of an atypical nevus is based on the visual recognition of certain characteristics: diameter >5 mm, prominent macular component (sometimes with a “fried egg” or “target” appearance), asymmetry, irregular borders, and variegated colors.1 The identification of atypical nevi is important as these lesions: (1) can mimic cutaneous melanoma, (2) increase an individual’s risk of developing cutaneous melanoma,2 and (3) on rare occasions, can be potential precursors of melanoma (ie, melanoma may arise in association with an atypical nevus). Although precise estimates of the risk of malignant transformation are lacking, one study estimated a risk of less than 1 per 30,000 per year.3

Physician-based screening for melanoma through full-body skin examination (ideally using dermoscopy) should be considered in individuals with atypical nevi. For lesions with diagnostic uncertainty and concern for a possible melanoma, an excisional biopsy with 1 to 3 mm margins is recommended.


The rationale for treatment of biopsied dysplastic nevi is two-fold. First, incompletely sampled lesions may have foci of malignancy or higher-grade atypia that were not identified with the initial biopsy. Second, melanomas have been reported to occur at sites of partially biopsied dysplastic nevi. Thus, in appropriately selected cases, excision or rebiopsy may reduce the possibility of misdiagnosis and/or the risk of future melanoma occurrence.

When considering postbiopsy treatment recommendations for dysplastic nevi, one should review the prebiopsy probability of melanoma, the adequacy and type of biopsy used in sampling the lesion, the degree of histopathological atypia (ie, mild, moderate, or severe atypia), the biopsy margin status, patient worry/anxiety and preferences, and the ability of the patient to monitor the site for future change. Grading the atypia of dysplastic nevi is not universally accepted but is frequently used by clinicians to guide clinical decisions.6,7 A common criticism raised with grading atypia is poor interrater reliability.1 The authors suggest that all of the above factors be considered in shared medical decision-making with patients. See Table 107-1.

Table 107-1Suspicious Skin Lesion Clinical Scenario Table.

In general, there is ...

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