title: Evaluation of perineurial differentiation in epithelioid sarcoma.
abstract: OBJECTIVE
  To investigate the differentiation pattern of epithelioid sarcoma in terms of perineurial and endothelial differentiation, and its relationship to that of meningioma.
  
  
  RESULTS
  Nine cases of epithelioid sarcoma and five cases of meningioma were studied in an immunohistochemical analysis of 'perineurial' antigens [GLUT-1, claudin-1, epithelial membrane antigen (EMA) and VE-cadherin] and of 'endothelial' antigens not present on normal perineurium (CD34, CD31, Fli-1). Both epithelioid sarcoma and meningioma showed frequent expression of the perineurial markers GLUT-1, claudin-1 and EMA. VE-cadherin was identified in one of five meningiomas, and in the only case of epithelioid sarcoma in which suitably fixed material was available. CD34 was expressed by all epithelioid sarcomas studied but by none of the meningiomas. Fli-1 was present in a substantial majority of epithelioid sarcomas and by all the meningiomas. CD31 was not detected in any epithelioid sarcoma or meningioma.
  
  
  CONCLUSIONS
  The results were evaluated in the context of previous immunohistochemical, ultrastructural and genetic studies and suggest that epithelioid sarcoma may be a form of malignant perineurioma with a range of differentiation (epithelial features) akin to that seen in meningioma, reflecting the close relationship between perineurium and meningothelium.
authors.affiliation: Histopathology, Derriford Hospital, Plymouth, London, UK. mark.smith@phnt.swest.nhs.uk
authors.forename: M E F
authors.initials: ME
authors.lastname: Smith
authors.forename: R
authors.initials: R
authors.lastname: Awasthi
authors.forename: S
authors.initials: S
authors.lastname: O'Shaughnessy
authors.forename: C
authors.initials: C
authors.lastname: Fisher
mesh_terms: D015703:Antigens, CD; D018952:Antigens, CD34 / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism; D002454:Cell Differentiation; D062445:Claudin-1; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism; D018396:Mucin-1 / Q000378:metabolism; D018317:Nerve Sheath Neoplasms / Q000378:metabolism / Q000473:pathology; D010525:Peripheral Nerves / Q000166:cytology / Q000378:metabolism*; D051789:Proto-Oncogene Protein c-fli-1 / Q000378:metabolism; D012509:Sarcoma / Q000378:metabolism* / Q000473:pathology; D012680:Sensitivity and Specificity; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D015820:Cadherins; D062445:Claudin-1; D051272:Glucose Transporter Type 1; D008565:Membrane Proteins; D018396:Mucin-1; D051789:Proto-Oncogene Protein c-fli-1; D000099152:Cadherin 5; C568108:CLDN1 protein, human