title: Solitary fibrous tumor of the orbit: a case series.
abstract: OBJECTIVE
  Solitary fibrous tumor (SFT) occurs rarely in the orbit. We present four such cases, representing one of the largest case series reported to date of this rare orbital tumor.
  
  
  METHODS
  The four patients ranged from ages 20 to 50, all of whom presented with lid swelling or bulging in the involved eye. All four patients underwent CT scan to confirm the diagnosis of an orbital mass, which was then excised.
  
  
  RESULTS
  The tumors of all four specimens contained spindle-shaped cells with bland nuclei and rare mitotic figures. They all stained positively with CD34 and vimentin. Resection margins were positive in two of the four cases. One of these cases demonstrated residual tumor on follow-up CT scan, which remained unchanged at one-year follow-up. No evidence of residual tumor was found in the other three cases, despite one having malignant pathology.
  
  
  CONCLUSIONS
  SFT is a rare and generally benign tumor of the orbit. Immunohistochemical testing with CD34 is necessary to confirm the diagnosis. Although en bloc tumor resection is the definitive treatment, residual tumor may remain stable for some time. However, this must be followed closely if complete resection is not carried out.
authors.affiliation: St. Michael's Hospital, Department of Ophthalmology, University of Toronto, Toronto, Canada.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Tam
authors.forename: Edmund C
authors.initials: EC
authors.lastname: Chen
authors.forename: Navdeep
authors.initials: N
authors.lastname: Nijhawan
authors.forename: John T
authors.initials: JT
authors.lastname: Harvey
authors.forename: David
authors.initials: D
authors.lastname: Howarth
authors.forename: James H
authors.initials: JH
authors.lastname: Oestreicher
mesh_terms: D000328:Adult; D018952:Antigens, CD34 / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D005350:Fibroma / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009918:Orbital Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D014746:Vimentin / Q000032:analysis
chemical_list: D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D014746:Vimentin