Congenital melanocyte nevi in the very young tend to be benign.
HISTOPATHOLOGY FINDINGS of cytologic atypia, architectural disorder, and pagetoid spread are common in congenital melanocytic nevi (CMN) of all sizes in children aged 0-35 months, and tend to have benign outcomes, according to a retrospective study.
Emily A. Simons, MPH, and her associates at Boston Children's Hospital studied 197 nevi in 179 patients with an average age of 14 months (range, 4 days to 35 months); 51% were female. Of those, 80% had skin types I-II, and 90% were white. The majority of the lesions involved the head or trunk and were predominantly medium in size, and 58% had a projected adult size of 1.5-10 cm. The study was retrospective; cases had been diagnosed between 1993 and 2013.
Cytologic atypia, architectural disorder, and pagetoid spread were the most frequent features--they were present in 73% of nevi and were closely associated. Combined histologic patterns of a blue nevus, spindle and Spitz nevus, or a deep penetrating nevus were identified in 40% of CMN. Proliferative nodules occurred in 5% of nevi.
Clinical outcomes were available for 130 patients, including 26 with large CMN and 8 with proliferative nodules. The children were alive and had not been diagnosed with melanoma at a mean follow-up of a mean of 8.4 years (range, 7 months to 21.3 years), even though margins of the last excision were positive in 41% of all CMN and in 77% of large CMN.
Malignant transformation of CMN certainly should be recognized, but the morbidity of overdiagnosis also needs to be considered. "Excision of larger CMN might require serial excisions under general anesthesia, the use of tissue expanders, and grafts," Dr. Simons and her associates said.
Among the limitations of this study were that the majority of patients were white, so the results may not translate to children with darker skin types, they noted.
"The diagnosis of malignant melanoma should be made with great caution in this population," they concluded, pointing out that the histopathologic features alone (cytologic atypia, architectural disorder, and pagetoid spread) "should not be interpreted as evidence for potential malignant behavior or serve as grounds for further excision."
The study was published in the Journal of the American Academy of Dermatology (2017 May;76941-7).
The authors had no relevant financial disclosures.
BY CATHERINE COOPER NELLIST
FROM THE JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY
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|Title Annotation:||PEDIATRIC DERMATOLOGY|
|Author:||Nellist, Catherine Cooper|
|Date:||Jun 1, 2017|
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