title: Papular epidermal nevus with "skyline" basal cell layer (PENS).
abstract: BACKGROUND
  Several types of epidermal keratinocytic nevus are recognized.
  
  
  OBJECTIVE
  We sought to describe a previously unreported keratinocytic nevus with distinctive clinical and histopathologic features in 5 patients.
  
  
  METHODS
  We performed a clinical and photographic review, and obtained skin biopsy samples for histopathologic examination from each patient. Genetic analysis to screen for fibroblast growth factor receptor 3 and phosphatidylinositol 3-kinase, catalytic, alpha hotspot mutations was performed on lesional skin from two patients.
  
  
  RESULTS
  Five infants (2 male, 3 female) had from 1 to 11 lesions present since birth. These consisted of 1- to 7-mm hyperkeratotic papules with a rough, flat surface and a round, commalike, rectangular, or polygonal shape. Histopathologic examination showed acanthosis with broad and rectangular rete ridges, and strikingly arranged basal cells with palisaded nuclei. Genetic testing on paraffin-embedded specimens from two patients ruled out hotspot mutations in the fibroblast growth factor receptor 3 and phosphatidylinositol 3-kinase, catalytic, alpha genes.
  
  
  CONCLUSIONS
  A small number of patients are presented.
  
  
  CONCLUSIONS
  We propose the name "papular epidermal nevus with 'skyline' basal cell layer" (PENS) for this newly recognized condition.
authors.affiliation: Department of Dermatology, Hospital del Niño Jesús, Madrid, Spain. atorrelo@aedv.es
authors.forename: Antonio
authors.initials: A
authors.lastname: Torrelo
authors.forename: Isabel
authors.initials: I
authors.lastname: Colmenero
authors.forename: Leonard
authors.initials: L
authors.lastname: Kristal
authors.forename: Lourdes
authors.initials: L
authors.lastname: Navarro
authors.forename: Christian
authors.initials: C
authors.lastname: Hafner
authors.forename: Angela
authors.initials: A
authors.lastname: Hernández-Martín
authors.forename: Luis
authors.initials: L
authors.lastname: Requena
authors.forename: Rudolf
authors.initials: R
authors.lastname: Happle
mesh_terms: D001913:Bowen's Disease / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D015603:Keratinocytes / Q000473:pathology; D008297:Male; D009506:Nevus / Q000235:genetics / Q000473:pathology*; D058539:Phosphatidylinositol 3-Kinase / Q000235:genetics / Q000378:metabolism; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics / Q000378:metabolism; D012878:Skin Neoplasms / Q000235:genetics / Q000473:pathology*; D009626:Terminology as Topic
chemical_list: D058539:Phosphatidylinositol 3-Kinase; D051498:Receptor, Fibroblast Growth Factor, Type 3