title: Lymphomatoid papulosis in children: a retrospective cohort study of 35 cases.
abstract: BACKGROUND
  Lymphomatoid papulosis (LyP) is a rare entity, considered to be part of the spectrum of the CD30(+) cutaneous lymphoproliferative disorders. About 10% to 20% of the adult LyP patients will develop an associated lymphoid malignancy. Only a few cases of LyP have been described in children, and the risk of associated lymphoid malignancies in these patients is not known.
  
  
  OBJECTIVE
  To study the association between childhood onset of LyP and other malignancies and to determine the clinical characteristics in this subgroup of patients.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Referral center at a university hospital. Retrospective registry for patients with LyP of childhood onset (< or =18 years). Patients Thirty-five patients with childhood-onset LyP (19 boys and 16 girls) were interviewed by telephone using a standardized questionnaire. The median duration of follow-up was 9.0 years. All included patients were confirmed by histologic examination.
  
  
  RESULTS
  The age distribution was significantly different, with boys having an earlier onset of LyP (P =.03). Of the 35 LyP patients, 3 (9%) developed a malignant lymphoma; all were diagnosed as having non-Hodgkin lymphoma. Compared with the general population, patients with childhood-onset LyP have a significantly increased risk of developing non-Hodgkin lymphoma (relative risk, 226.2; 95% confidence interval, 73.4-697.0). More than two thirds of the patients reported being atopic, which is significantly more than the expected prevalence of atopy (relative risk, 3.1; 95% confidence interval, 2.2-4.3).
  
  
  CONCLUSIONS
  Lymphomatoid papulosis presents similarly in children and adults, including the risk of lymphoid malignancies. Therefore, all LyP patients should be closely monitored throughout their lives.
authors.affiliation: Department of Dermatology, the Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass. 02215, USA.
authors.forename: Tamar
authors.initials: T
authors.lastname: Nijsten
authors.forename: Clara
authors.initials: C
authors.lastname: Curiel-Lewandrowski
authors.forename: Marshall E
authors.initials: ME
authors.lastname: Kadin
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006785:Hospitals, University; D006801:Humans; D017731:Lymphomatoid Papulosis / Q000453:epidemiology* / Q000209:etiology* / Q000473:pathology; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D012042:Registries; D012189:Retrospective Studies; D011795:Surveys and Questionnaires