title: The High Multiplicity of Prenatal (Congenital Type) Nevi in Adolescents and Adults.
abstract: In the absence of work on prenatal nevogenesis, it has long been necessary to define congenital melanocytic nevi by clinical detection on neonatal skin examination. They are seen in approximately 1% of newborns, with multiplicity in approximately 3% of cases. Melan-A staining of grossly normal fetal skin recently demonstrated fetal nevi, whose features validated certain traditional histologic criteria for "congenital type" nevi that may not have been detectable at birth. This suggested that many clinically acquired nevi actually formed in utero, like congenital nevi. Prenatal nevi has been suggested as a preferred synonym for "congenital type" nevi. Prenatal nevi were detected in 6 of 25 fetuses (24%), a strikingly higher incidence than congenital nevi in newborns. In this series of 354 patients with prenatal (congenital type) nevi encountered in routine practice at a community hospital, over 30% of both adolescents and adults had multiple prenatal nevi; a strikingly higher rate of multiplicity than congenital nevi in newborns. This high multiplicity may reflect origin beneath the epidermis, with many prenatal nevi working their way up to the surface of the skin decades after birth.
authors.affiliation: 1 Department of Pathology, Rochester General Hospital, University of Rochester School of Medicine, Rochester, NY, USA.
authors.forename: Stewart F
authors.initials: SF
authors.lastname: Cramer
authors.affiliation: 2 Department of Pathology, University of Pittsburgh School of Medicine, and Division of Pediatric Pathology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA.
authors.forename: Cláudia M
authors.initials: CM
authors.lastname: Salgado
authors.affiliation: 2 Department of Pathology, University of Pittsburgh School of Medicine, and Division of Pediatric Pathology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA.
authors.forename: Miguel
authors.initials: M
authors.lastname: Reyes-Múgica
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008544:Melanocytes / Q000473:pathology; D009508:Nevus, Pigmented / Q000151:congenital* / Q000473:pathology*; D012878:Skin Neoplasms / Q000151:congenital* / Q000473:pathology*; D055815:Young Adult