title: Lymphomatoid Papulosis in Children and Adolescents: A Systematic Review.
abstract: BACKGROUND
  Lymphomatoid papulosis (LyP) is a lymphoproliferative disorder that is rare among adults and even rarer among children. In adults, LyP is associated with an increased risk of secondary lymphomas.
  
  
  OBJECTIVE
  The aim of this systematic review was to describe the clinical and histopathological features of LyP in children, to assess the risk of associated lymphomas, and to compare the disease to the adult form.
  
  
  METHODS
  A systematic review was conducted using the MEDLINE (PubMed), EMBASE, Scopus, and Cochrane databases from inception to June 2015. Articles were included if data were extractable from studies, case series, and single reports of pediatric LyP patients.
  
  
  RESULTS
  A total of 251 children and adolescents with LyP were identified, with the mean age at diagnosis being 9.3 ± 4.6 years (n = 187). The female to male ratio was 1:1.4, and the majority of children reported on were Caucasian (n = 74, 85.1 %). The predominant histologic subtype was type A (n = 106, 79.1 %). Clinically, LyP lesions presented as erythematous papules or nodules, appearing preferentially on the extremities and the trunk. LyP has to be differentiated from pityriasis lichenoides (PL) and primary cutaneous anaplastic large cell lymphoma (ALCL). PL and associated lymphomas were diagnosed before, with, and after LyP in 19 and 14 cases, respectively. Of the 14 subjects with associated lymphomas, two children developed systemic ALCL.
  
  
  CONCLUSIONS
  LyP has to be differentiated from ALCL to avoid erroneous treatments. Due to the increased risk of development of non-Hodgkin lymphomas, lifelong follow-up and proper patient counseling are warranted.
authors.affiliation: Department of Dermatology, The University of Texas, MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX, 77030-4095, USA. iris.wieser@hotmail.com.|Department of Dermatology, Paracelsus Medical University, Salzburg, Austria. iris.wieser@hotmail.com.
authors.forename: Iris
authors.initials: I
authors.lastname: Wieser
authors.affiliation: Paracelsus Medical University, Salzburg, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Wohlmuth
authors.affiliation: Department of Pediatric Oncology, Division of Pediatrics, The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Cesar A
authors.initials: CA
authors.lastname: Nunez
authors.affiliation: Department of Dermatology, The University of Texas, MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX, 77030-4095, USA.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Duvic
mesh_terms: D000293:Adolescent; D002648:Child; D006801:Humans; D008223:Lymphoma / Q000209:etiology*; D017731:Lymphomatoid Papulosis / Q000150:complications* / Q000473:pathology*; D012307:Risk Factors; D012878:Skin Neoplasms / Q000150:complications* / Q000473:pathology*