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Degree of dysplastic nevi determined effectiveness of excision

Patients with biopsy-diagnosed moderately to severely dysplastic nevi experienced greater benefits after excisions than patients with mildly or moderately dysplastic nevi, according to study results.

Researchers conducted a national retrospective review at a Boston academic dermatopathology practice of 580 cases reporting a biopsy diagnosis of dysplastic nevus. Systematized nomenclature of medicine codes was used to identify consecutive patient pathology samples of dysplastic nevi and cutaneous melanomas evaluated between Sept. 1, 1999 and March 1, 2011.

The rates of clinically significant change in diagnosis and melanoma detection as a result of excision were used as main outcomes and measures in the dysplastic nevi cases; the rate and characteristics of association with dysplastic nevi were used for melanoma cases.

Positive biopsy margins were reported in 196 (34%) of the dysplastic nevi. As the degree of atypia worsened, a positive biopsy was displayed more often (P<.001 for trend). One hundred twenty-seven of these nevi (65%) were excised, which occurred more frequently as the grade of atypia increased (P<.001, for trend).

Researchers said two excisions (1.6%) resulted in a clinically significant change in diagnosis, from biopsy-diagnosed moderately to severely dysplastic nevi before excision to melanoma in situ after the procedure.

In situ and superficial spreading subtypes of 216 melanomas more often were associated with dysplastic nevi (20% and 18%, respectively; P=.002), and were primarily moderate to severe or severe.

“Excision of biopsy-diagnosed mildly or moderately dysplastic nevi is unlikely to result in a clinically significant change in diagnosis, and risk of transformation to melanoma appears very low,” the researchers concluded. “Moderately to severely and severely dysplastic nevi are more often associated with melanoma, and excision may be beneficial for melanoma detection or prevention.”

Disclosure: The researchers report no relevant financial disclosures.