Margin comments in nevi histology reports impact re-excision rates

Panama City, Panama - Histological reports on atypical or dysplastic nevi that include margin comments appear to have a significant impact on how the clinician will proceed regarding the potential re-excision of lesions, according to a recent literature review.

“The literature has begun in a more scientific way to back up what we have already been doing in practice for the last 15 to 20 years regarding dysplastic nevi. It appears that dermatologists have been intuitively treating and managing these potentially dangerous lesions correctly, underscoring the safe medicine practiced by clinicians,” says Richard L. Spielvogel, M.D., Dermpath Diagnostics, Newtown Square, Pa.

In a recent study, researchers investigated the value of margin comments used in dermatopathology reports on dysplastic nevi and how they can influence re-excision rates. The retrospective study included 584 histopathologically dysplastic nevi, of which 302 had margin comments in the histology report and 282 did not. Results showed that re-excision was performed at a significantly higher rate in those patients who had a report without margin comments (51.8 percent) compared to patients where margin comments were included in the report (39.4 percent).

According to the study, the difference was observed among those nevi that were diagnosed as mildly to moderately dysplastic, but not for severely dysplastic nevi. Apart from the direct impact of potentially reducing the rates of re-excisions, the authors concluded that use of margin comments can also help reduce healthcare costs and morbidity (Comfere NI, et al. J Am Acad Dermatol. 2013;69(5):687-692).

Re-excision decision

Another study looked at the long-term outcomes of patients with histologically dysplastic nevi that approached a microscopic specimen border (within 0.2 mm) but were not re-excised. It questioned whether or not there was an increased risk for the lesions to further develop into a melanoma (Hocker TL, et al. J Am Acad Dermatol. 2013;68(4):545-551).

The retrospective study included a total of 115 patients who were followed-up for an average of 17.4 years. Of the 115 nevi included in the study, 66, 42 and seven nevi had mild, moderate and severe dysplasia, respectively. Results showed that none of the patients developed metastatic melanoma or melanoma at the site where the dysplastic nevus was originally removed, despite the fact it closely approached a margin.

“Both of these studies indicate that clinicians do not necessarily have to routinely re-excise dysplastic nevi that were incompletely or narrowly removed, particularly those nevi with only very mild or moderate atypia. However, those nevi exhibiting severe atypia should be re-excised,” Dr. Spielvogel says.

The excision and/or re-excision of severely dysplastic nevi is still recommended Dr. Spielvogel said, because of the possibility that they could further develop into a melanoma. Moreover, severely atypical lesions cannot be reliably distinguished from melanoma in all instances, and they should be removed just to be on the safe side. In practice, Dr. Spielvogel said that some dermatologists may prefer to also re-excise moderately dysplastic nevi that have been incompletely or narrowly removed however, that would be an individual decision.

“Regardless of the pathology report, if a lesion looks severely unusual or atypical on clinical presentation, it should be completely removed with a clear margin,” Dr. Spielvogel says. “It is important to remember that pathology consists of both a gross, which only the dermatologist sees, and a pathologic, which only the pathologist sees. If either one appears severely atypical, that could be an overriding factor and the lesion in question should be completely removed.”

Diagnostic differences

In another retrospective study, researchers evaluated the effect of surgical excision performed after the biopsy-diagnosis of dysplastic nevi, in terms of the final diagnosis, melanoma prevention and melanoma detection (Reddy KK, et al. JAMA Dermatol. 2013;149(8):928-934). Of the 580 dysplastic nevi included in the study, 196 had a positive biopsy margin increasing with grade of atypia; 127 of the 196 lesions (65 percent) were re-excised, performed more often as the grade of atypia increased.

Data showed that two of the 127 re-excised lesions received a different diagnosis, changing from biopsy-diagnosed moderately to severely dysplastic nevus to melanoma in situ. The researchers also found that of the 216 melanomas included in the study, in situ and superficial spreading subtypes were more often associated with histopathologically dysplastic nevi (20 percent and 18 percent, respectively), most of them having a moderate-to-severe grade of atypia.

The excision of biopsy-diagnosed mildly or moderately dysplastic nevi will not likely result in a clinically significant change in diagnosis, Dr. Spielvogel says, and the risk of transformation of these lesions to melanoma appears very low. However, as moderately-to-severely and severely dysplastic nevi are more often associated with melanoma, their timely excision may be prove to be beneficial for the detection or prevention of melanoma.

“There has been a lot of controversy on atypical or dysplastic nevi regarding their appropriate treatment and management. I think that despite the lack of literature in the past, it looks like most practicing dermatologists have come to some good conclusions regarding when to re-excise the lesion, and which types of lesions (in terms of their atypia) to re-excise, as reflected in these recent studies,” Dr. Spielvogel says.

Disclosures: Dr. Spielvogel reports no relevant financial interests.