title: Mast cell distribution, activation, and phenotype in xanthoma.
abstract: BACKGROUND
  Activated mast cells enhance the uptake of mast cell-derived proteoglycan-low-density lipoprotein complexes by macrophages.
  
  
  OBJECTIVE
  We sought to investigate mast cell contribution to the pathogenesis of xanthoma.
  
  
  METHODS
  Twenty cases of xanthelasma palpebrarum and 6 cases of tuberous xanthoma lesions were analyzed using immunohistochemical staining.
  
  
  RESULTS
  Xanthelasma lesions contained up to 5-fold more tryptase-stained mast cells than tuberous xanthoma lesions. Tuberous xanthoma lesions especially showed extensive staining of tryptase around mast cells and within some macrophages and foam cells. More than 99% of mast cells in xanthelasma lesions contained both tryptase and chymase. Approximately 60% of mast cells represented only tryptase in tuberous xanthoma lesions where the ratio of macrophages to tryptase-stained mast cells was extremely high (15:1) as compared with xanthelasma lesions (2:1).
  
  
  CONCLUSIONS
  A change in mast cell phenotype has not been necessarily proven.
  
  
  CONCLUSIONS
  Mast cells are activated under the microenvironment in which macrophages predominate rather than mast cells, which thus reflects the clinical phenotypes of xanthoma lesions.
authors.affiliation: Department of Dermatology, Kochi Medical School, Kochi, Japan. matsumo@med.kochi-u.ac.jp
authors.forename: Masaaki
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Sawa
authors.initials: S
authors.lastname: Kunimitsu
authors.forename: Kana
authors.initials: K
authors.lastname: Wada
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Ikeda
authors.forename: Akira
authors.initials: A
authors.lastname: Keyama
authors.forename: Hajime
authors.initials: H
authors.lastname: Kodama
mesh_terms: D000368:Aged; D002454:Cell Differentiation / Q000502:physiology; D053818:Chymases / Q000378:metabolism; D004396:Coloring Agents; D005260:Female; D005487:Foam Cells / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D008407:Mast Cells / Q000378:metabolism*; D008875:Middle Aged; D010641:Phenotype; D012867:Skin / Q000378:metabolism; D014048:Tolonium Chloride; D053802:Tryptases / Q000378:metabolism; D014973:Xanthomatosis / Q000378:metabolism*
chemical_list: D004396:Coloring Agents; D014048:Tolonium Chloride; D053818:Chymases; D053802:Tryptases