Physician Blog

Not All Atypical Nevi Are Precancerous

by Gary L. Peck, M.D. | May 8, 2019

Dr. Peck is a board certified dermatologist that began his career at the National Institutes of Health in the Dermatology Branch of the National Cancer Institute. He founded and served as director of the Melanoma Center at the Washington Hospital Center. Dr. Peck is a recipient of the Discovery Award of the Dermatology Foundation, the highest award in Dermatology in recognition of his discovery of isotretinoin for the treatment of severe, recalcitrant nodulocystic acne and other disorders, including the prevention of basal cell carcinomas.

No one wants to miss a melanoma when examining a patient. Since severely atypical nevi and early melanomas may be indistinguishable on clinical exam, no one wants to leave such a lesion unbiopsied. Having said that, it is somewhat of an overdiagnosis to equate lesions that are diagnosed as mildly or moderately atypical by a pathologist as definitely precancerous.

Recent publications have documented that re-excisions of moderately atypical nevi, for example, extremely rarely will demonstrate a melanoma. In my own experience I have never had a melanoma upon re-excision of a moderately atypical nevus that clinically appeared completely or almost completely excised by the original biopsy.” Most re-excisions show only scar tissue from the original biopsy or, less commonly, small residual atypical nevi. These articles call for simple close monitoring of patients with the atypical mole syndrome or those with a history of moderately atypical nevi rather than wholesale biopsy of large numbers of benign lesions.

My experience as originator and director of the melanoma center, and later as director emeritus, at the Washington Hospital Center in Washington DC from 1996 to 2015 was that we accrued about 2000 melanoma patients. Many of our patients at the melanoma center had a history of multiple biopsies of benign or mildly atypical nevi that left scars that the patients objected to.

The PLA improves our specificity and reduces the number of unnecessary biopsies we perform on clinically atypical lesions.

Since 1996 we have relied upon dermoscopic evaluation of our patient’s nevi to determine which lesions to biopsy. The routine use of dermoscopy has increased our diagnostic ability and has reduced the number of unnecessary biopsies.

“I have been using the PLA in clinic since 2015 to test clinically and dermoscopically atypical lesions. The PLA improves our diagnostic ability and enables us to diagnose smaller melanomas at an earlier stage.”

Since 2015 we have added PLA testing of clinically and dermoscopically atypical lesions to our clinic routine. As such, we are able to diagnose smaller melanomas at an earlier stage. Almost all of the melanomas we have diagnosed since I joined the Dermatologic Surgery Center of Washington have been small melanomas in situ. Thus, we have found that PLA testing is sensitive and reliable and is a useful adjunct to dermoscopy in increasing the specificity of our biopsies.