title: A clinical and pathologic study of histiocytosis X in adults.
abstract: BACKGROUND
  Histiocytosis X is a neoplastic disorder of Langerhans cells that usually occurs in children. Because histiocytosis X rarely occurs in adults, the diagnosis can frequently be missed by both clinicians and pathologists.
  
  
  OBJECTIVE
  The purpose of this investigation was to characterize the clinical and pathologic findings of histiocytosis X in adults.
  
  
  METHODS
  A retrospective study of four adults with histiocytosis X was undertaken. Paraffin-embedded biopsy specimens were stained with a panel of antibodies including S-100, vimentin, Ham-56, leukocyte common antigen, proliferating cell nuclear antigen (PCNA), UCHL-1, CD43, and Ki-1.
  
  
  RESULTS
  The predominant lesions were papules and pustules that usually involved the groin, axilla, and scalp. Histologically the infiltrate exhibited a periappendageal distribution. Strong positive staining for PCNA appeared to correlate with the clinical course.
  
  
  CONCLUSIONS
  Histiocytosis X in adults has a predilection for skin sites rich in appendages and histologically shows a periappendageal infiltrate. PCNA staining of the histiocytes may indicate progressive disease and serve as a useful prognostic marker.
authors.affiliation: Division of Dermatology/Department of Medicine, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey.
authors.forename: K F
authors.initials: KF
authors.lastname: Helm
authors.forename: D P
authors.initials: DP
authors.lastname: Lookingbill
authors.forename: J G
authors.initials: JG
authors.lastname: Marks
mesh_terms: D000328:Adult; D001324:Autoantigens / Q000032:analysis; D001365:Axilla; D005260:Female; D006119:Groin; D006646:Histiocytosis, Langerhans-Cell / Q000473:pathology*; D006801:Humans; D008875:Middle Aged; D009687:Nuclear Proteins / Q000032:analysis; D018809:Proliferating Cell Nuclear Antigen; D012189:Retrospective Studies; D009418:S100 Proteins / Q000032:analysis; D012536:Scalp Dermatoses / Q000473:pathology; D014746:Vimentin / Q000032:analysis
chemical_list: D001324:Autoantigens; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D009418:S100 Proteins; D014746:Vimentin