Caroline Kim, MD
When dermatologists encounter patients with atypical melanocytic lesions, the prospect of evaluating and managing these patients is particularly challenging. These patients can present with numerous nevi that can be difficult to differentiate from melanoma, and their nevi can have complex, heterogeneous patterns.
During the Saturday Forum, “Practical Management of Atypical Melanocytic Lesions,” presenters provided strategies to help evaluate and monitor patients with truncal and extremity, scalp and facial, and acral lesions.
“Patients with atypical nevi are at higher risk for melanomas, yet atypical nevi themselves are not on a progression to becoming melanomas,” said Forum Director Caroline Kim, MD. “Data suggest that the majority of melanomas arise de novo, while a smaller percent arise from within a nevus, either dysplastic or common.
“The challenge for care providers is to be able to screen for and identify a melanoma in these complex patients, but, at the same time, not remove a large number of their nevi unnecessarily. Different sites of the body have unique challenges.”
While being faced with a patient with numerous atypical nevi can be overwhelming, she recommended identifying signature nevus patterns first, then looking for the “ugly duckling.”
“Jean Bolognia, MD, described looking at a moley patient on ‘low power’ as a pathologist first looks at a slide,” said Dr. Kim, director of the Pigmented Lesion Clinic at Beth Israel Deaconess Medical Center and assistant professor of dermatology at Harvard Medical School, Boston. “You will find that even very complicated patients tend to make patterns of similar types of moles, and then you can find and look at outliers more closely clinically and with dermoscopy to decide if they are suspicious for melanoma. By pattern analysis, you’ll more easily find the ugly duckling — this is a concept you can teach patients.
“Atypical nevi do not need to be biopsied to prove they are atypical if they are stable and do not have melanoma warning features. Rather, we should be biopsying lesions when we are concerned about melanoma.”
In describing the practical management of atypical melanocytic lesions, Dr. Kim noted that current AAD and National Comprehensive Cancer Network guidelines recommend an excisional biopsy approach for lesions suspicious for melanoma, but no guidelines are in place for a biopsy that results in a dysplastic nevus with positive histologic margins.
“Currently, management is variable across the country for dysplastic nevi with positive margins, which causes much confusion. More data is needed to evaluate the role of re-excision versus observation for certain grades of dysplasia. Observation may be a reasonable option for mildly and moderately dysplastic nevi with positive histologic margins but with no clinical residual lesion, but more data would be needed to confirm this,” she said. “Regardless, any biopsy site of any nevus should be monitored for unusual regrowth to exclude melanoma.”
Kelly C. Nelson, MD, assistant professor of dermatology at Duke University, Durham, N.C., reviewed unknown cases and correlating dermoscopy photos on all body sites to identify dermoscopy features for difficult pigmented lesions. She showed patient cases where in an older population, peripheral pigmented globules and lack of arborizing vessels in amelanotic lesions tipped her off to a diagnosis of melanoma.
Clara Curiel-Lewandrowski, MD, associate professor of dermatology and director of the Pigmented Lesion Clinic at the University of Arizona, Tucson, described the management of atypical scalp and facial melanocytic lesions with case examples. These locations can be challenging because it can be difficult to differentiate melanoma from some mimickers, such as lentigines, seborrheic keratosis, and even basal cell carcinoma. Dr. Curiel-Lewandrowski illustrated strategies, such as serial photography and confocal microscopy, as well as multiple biopsies of larger lesions to help evaluate lesions.
Jennifer Stein, MD, assistant professor and associate director of the pigmented lesion service at New York University Langone Medical Center, discussed the challenges of acral lesions, including unique dermoscopy features, difficulty in self-monitoring, and biopsies being more challenging to perform in this location.
She emphasized that dermoscopically, “furrows are fine, but ridges are risky,” meaning lesions with parallel pigment in the furrows are benign while those with pigment over the ridges should be considered suspicious for melanoma. She also described the “peas in a pod” sign, which illustrates dots on eccrine units of the ridges with parallel furrow lines and is indicative of a benign congenital nevus.
Michael Ming, MD, MSCE, associate professor of dermatology and director of the Pigmented Lesion Clinic at the University of Pennsylvania, discussed decisions about where and how to biopsy atypical melanocytic lesions by presenting cases from his clinic that had biopsy-related dilemmas. He showed how large lesions were partially sampled, and stressed that sampling biopsies may not be accurate representations of the entire lesion. Dr. Ming recommended that each patient should receive an individualized approach based on the individual circumstance and preferences of the patient.