title: A comparative study of proliferative nodules and lethal melanomas in congenital nevi from children.
abstract: Differentiating proliferative nodules (PNs) from melanomas arising in congenital nevi (CN) is a considerable challenge for dermatopathologists. Most of the specimens dermatopathologists assess that deal with this differential diagnosis involve proliferations of melanocytes arising in the dermis. In this study, we compare the clinical, histologic, and molecular findings of these 2 conditions. In our database, we found 22 examples of PNs arising in the dermis of CN and 2 cases of lethal melanomas arising from the dermis/epidermis of CN of children. Importantly, we found that among dermal melanocytic proliferations arising from CN in children, PNs are far more common than lethal melanomas. Clinically, multiplicity of lesions favored a diagnosis of PNs, whereas ulceration was infrequent in PNs compared with lethal melanomas. Histologically, PNs showed several distinct patterns including expansile nodules of epithelioid melanocytes with mitotic counts lower than that seen in the melanomas (1.67 vs. 12.5 mitoses/mm), a small round blue cell pattern often highly mitotically active, neurocristic-like, blue nevus-like, a nevoid melanoma-like pattern, or an undifferentiated spindle cell pattern. The lethal melanomas both featured expansile nodules of epithelioid melanocytes with high mitotic counts (range, 5 to 20 mitoses/mm) and an ulcerated overlying epidermis. At the molecular level, the PNs showed mostly whole chromosomal copy number aberrations, which in some cases were accompanied by rare partial chromosomal aberrations, whereas both lethal melanomas showed highly elevated copy number aberrations involving 6p25 without gains of the long arm of chromosome 6.
authors.affiliation: *Department of Dermatology §Robert H. Lurie Cancer Center ‡Department of Pediatric Dermatology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University †Department of Pathology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL.
authors.forename: Oriol
authors.initials: O
authors.lastname: Yélamos
authors.forename: Nicoleta C
authors.initials: NC
authors.lastname: Arva
authors.forename: Roxana
authors.initials: R
authors.lastname: Obregon
authors.forename: Pedram
authors.initials: P
authors.lastname: Yazdan
authors.forename: Annette
authors.initials: A
authors.lastname: Wagner
authors.forename: Joan
authors.initials: J
authors.lastname: Guitart
authors.forename: Pedram
authors.initials: P
authors.lastname: Gerami
mesh_terms: D000293:Adolescent; D000367:Age Factors; D014408:Biomarkers, Tumor / Q000235:genetics; D049109:Cell Proliferation; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002896:Chromosomes, Human, Pair 6; D055028:Comparative Genomic Hybridization; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008544:Melanocytes / Q000473:pathology*; D008545:Melanoma / Q000401:mortality / Q000473:pathology*; D008940:Mitotic Index; D018330:Nevus, Intradermal / Q000151:congenital / Q000401:mortality / Q000473:pathology*; D009508:Nevus, Pigmented / Q000151:congenital / Q000401:mortality / Q000473:pathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000151:congenital / Q000401:mortality / Q000473:pathology*; D012883:Skin Ulcer / Q000473:pathology; D013997:Time Factors; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor