title: Osteopontin expression in biopsies of calciphylaxis.
abstract: BACKGROUND
  Calciphylaxis combines features of vascular thrombotic occlusion and endoluminal calcification. In this study we examine the expression of osteopontin as a diagnostic marker and its role in lesional pathogenesis.
  
  
  METHODS
  25 formalin-fixed, paraffin embedded skin biopsies of 20 females and 5 males (mean age of 60 years) with a diagnosis of calciphylaxis were assessed for osteopontin expression.
  
  
  RESULTS
  Lower extremities were the most commonly involved areas; however a truncal and genital distribution was also noted in 3 cases. Renal failure was present in 21 of 25 cases. One patient had myeloproliferative disorder and one patient had advanced colon cancer. The dominant pathology was localized to the subcutaneous fat, characterized by mural calcification and luminal thrombosis affecting capillaries, venules, arterioles and small arteries. In 2 cases, a subcutaneous thrombogenic vasculopathy without calcification was noted. Osteopontin expression was confined to the subcutis, being most striking in calcified vessels but also apparent in vessels without calcification, including mineral poor variants of calciphylaxis.
  
  
  CONCLUSIONS
  Calciphylaxis represents a unique calcific thrombogenic vasculopathy, not limited to renal failure. Ectopic osteopontin expression may define a critical and initial event in the calciphylaxis pathogenesis. Therapeutic agents designed to reduce osteopontin expression may be of value in its treatment.
authors.affiliation: Department of Pathology, Laboratory Medicine, Weill Cornell Medical College of Cornell University, 1300 York Ave, New York, NY, 10065 USA.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Magro
authors.affiliation: Department of Pathology, Laboratory Medicine, Weill Cornell Medical College of Cornell University, 1300 York Ave, New York, NY, 10065 USA.
authors.forename: Shabnam
authors.initials: S
authors.lastname: Momtahen
authors.affiliation: Department of Dermatology, University of Pittsburgh Medical Center, 200 Lothrop St, Pittsburgh, PA, 15213 USA.
authors.forename: Joshua W
authors.initials: JW
authors.lastname: Hagen
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D002115:Calciphylaxis / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D053495:Osteopontin / Q000096:biosynthesis*; D012867:Skin / Q000378:metabolism* / Q000473:pathology
chemical_list: D015415:Biomarkers; D053495:Osteopontin
keywords: calciphylaxis; endoluminal calcification; osteopontin expression; thrombogenic vasculopathy