title: Papular Epidermal Nevus with Skyline Basal Cell Layer (PENS): Three New Cases and Review of the Literature.
abstract: Papular epidermal nevus with skyline basal cell layer (PENS) is a recently described type of epidermal nevus with characteristic histopathologic findings, mainly regular, rectangular acanthosis and a well-demarcated basal cell layer with clear palisading and separation between basal cell nuclei and the first row of Malpighian cell nuclei. Although the first reports described randomly distributed lesions appearing sporadically in otherwise healthy patients, cases of Blaschkoid distribution, lesions associated with extracutaneous manifestations, and familial cases have been reported.
  
  
  
  We performed a review of the clinical charts of all patients with histologic diagnosis of PENS in our hospital. We evaluated epidemiologic, clinical, and histologic features. We then reviewed the literature with a particular emphasis on the presence or absence of extra-cutaneous associations.
  
  
  
  Three patients with PENS are described. One had a single lesion, one had three lesions, and one, a patient with mild developmental delay, a curved penis, and hypospadias, had multiple lesions.
  
  
  
  The probability of having extracutaneous manifestations is 6.3 times as great in individuals with more than four lesions. Therefore these patients may need closer follow-up.
authors.affiliation: Dermatology Department, Hospital Alemán, Buenos Aires, Argentina.
authors.forename: Paula C
authors.initials: PC
authors.lastname: Luna
authors.affiliation: Dermatology Department, Hospital Alemán, Buenos Aires, Argentina.
authors.forename: Anabel A
authors.initials: AA
authors.lastname: Panizzardi
authors.affiliation: Dermatology Department, Hospital Alemán, Buenos Aires, Argentina.
authors.forename: Carolina I
authors.initials: CI
authors.lastname: Martin
authors.affiliation: Dermatology Department, Hospital Alemán, Buenos Aires, Argentina.
authors.forename: Felix
authors.initials: F
authors.lastname: Vigovich
authors.affiliation: Dermatology Department, Hospital Alemán, Buenos Aires, Argentina.
authors.forename: José G
authors.initials: JG
authors.lastname: Casas
authors.affiliation: Dermatology Department, Hospital Alemán, Buenos Aires, Argentina.
authors.forename: Margarita
authors.initials: M
authors.lastname: Larralde
mesh_terms: D001707:Biopsy, Needle; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D002675:Child, Preschool; D046169:Dermoscopy / Q000379:methods; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D009506:Nevus / Q000453:epidemiology* / Q000473:pathology* / Q000503:physiopathology; D009508:Nevus, Pigmented / Q000453:epidemiology / Q000473:pathology* / Q000503:physiopathology; D011379:Prognosis; D012878:Skin Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000503:physiopathology