title: Plasmacytoid dendritic cells in hypertrophic discoid lupus erythematosus: an objective evaluation of their diagnostic value.
abstract: BACKGROUND
  Hypertrophic discoid lupus erythematosus (HDLE), a rare variant of lupus skin disease, is difficult to distinguish from squamous neoplasms and certain dermatoses microscopically. Recently, recognition of the pathogenetic significance of plasmacytoid dendritic cells (PDCS) in cutaneous lupus erythematosus (LE) and of their patterns of distribution in different manifestations of the disease prompted us to study their diagnostic value in the context of HDLE.
  
  
  METHODS
  Using immunohistochemistry (CD123) to label the cells, we examined their quantities and patterns of distribution in 27 tissue samples of HDLE from nine patients compared with 39 inflammatory and neoplastic control samples from 36 patients.
  
  
  RESULTS
  Using three parameters pertaining to PDCs: (i) their representation of 10% or more of the inflammatory infiltrate, (ii) their arrangement in clusters of 10 cells or more and (iii) their presence at the dermoepidermal junction, we found them to have significant diagnostic value, with accuracies of 77%, 74% and 71%, respectively.
  
  
  CONCLUSIONS
  This study supports the careful descriptive observations of previous authors in the field. It also lends validity to the diagnostic step of mapping, immunohistochemically, the density and distribution of PDCs in suspected cases of HDLE.
authors.affiliation: Department of Pathology, Capital District Health Authority and Dalhousie University, Halifax, NS, Canada.
authors.forename: Noreen M
authors.initials: NM
authors.lastname: Walsh
authors.forename: Jonathan
authors.initials: J
authors.lastname: Lai
authors.forename: John G
authors.initials: JG
authors.lastname: Hanly
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Green
authors.forename: Francesca
authors.initials: F
authors.lastname: Bosisio
authors.forename: Juan
authors.initials: J
authors.lastname: Garcias-Ladaria
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cerroni
mesh_terms: D000328:Adult; D000368:Aged; D003713:Dendritic Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000473:pathology; D007150:Immunohistochemistry; D008178:Lupus Erythematosus, Cutaneous / Q000473:pathology; D008179:Lupus Erythematosus, Discoid / Q000175:diagnosis / Q000473:pathology*; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged
keywords: cutaneous lupus erythematosus; discoid lupus erythematosus; hypertrophic discoid lupus erythematosus; plasmacytoid dendritic cells