title: Meningeal Hemangiopericytomas and Meningomas: a Comparative Immunohistochemical and Genetic Study.
abstract: BACKGROUND
  The meningeal hemangiopericytoma (MHPC) is a vascular tumor arising from pericytes. Most intracranial MHPCs resemble meningiomas (MNGs) in their clinical presentation and histological features and may therefore be misdiagnosed, despite important differences in prognosis.
  
  
  METHODS
  We report 8 cases of MHPC and 5 cases of MNG collected from 2007 to 2011 from the Neuro-Surgery and Histopathology departments. All 13 samples were re reviewed by two independent pathologists and investigated by immunohistochemistry (IHC) using mesenchymal, epithelial and neuro-glial markers. Additionally, we screened all tumors for a large panel of chromosomal alterations using multiplex ligation probe amplification (MLPA). Presence of the NAB2-STAT6 fusion gene was inferred by immunohistochemical staining for STAT6.
  
  
  RESULTS
  Compared with MNG, MHPCs showed strong VIM (100% of cases), CD99 (62%), bcl-2 (87%), and p16 (75%) staining but only focal positivity with EMA (33%) and NSE (37%). The p21 antibody was positive in 62% of MHPC and less than 1% in all MNGs. MLPA data did not distinguish HPC from MNG, with PTEN loss and ERBB2 gain found in both. By contrast, STAT6 nuclear staining was observed in 3 MHPC cases and was absent from MNG.
  
  
  CONCLUSIONS
  MNG and MHPC comprise a spectrum of tumors that cannot be easily differentiated based on histopathology. The presence of STAT6 nuclear positivity may however be a useful diagnostic marker.
authors.affiliation: Department of Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia E-mail : dorrahmida@yahoo.fr.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Trabelsi
authors.forename: Nadia
authors.initials: N
authors.lastname: Mama
authors.forename: Maroua
authors.initials: M
authors.lastname: Chourabi
authors.forename: Maroua Haddaji
authors.initials: MH
authors.lastname: Mastouri
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ladib
authors.forename: Sergey
authors.initials: S
authors.lastname: Popov
authors.forename: Anna
authors.initials: A
authors.lastname: Burford
authors.forename: Moncef
authors.initials: M
authors.lastname: Mokni
authors.forename: Kalthoum
authors.initials: K
authors.lastname: Tlili
authors.forename: Hedi
authors.initials: H
authors.lastname: Krifa
authors.forename: Chris
authors.initials: C
authors.lastname: Jones
authors.forename: Mohamed Tahar
authors.initials: MT
authors.lastname: Yacoubi
authors.forename: Ali
authors.initials: A
authors.lastname: Saad
authors.forename: Dorra H'mida-Ben
authors.initials: DH
authors.lastname: Brahim
mesh_terms: D000071443:12E7 Antigen; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000032:analysis; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis / Q000235:genetics; D066246:ErbB Receptors / Q000235:genetics; D005260:Female; D006393:Hemangiopericytoma / Q000737:chemistry* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008577:Meningeal Neoplasms / Q000737:chemistry* / Q000235:genetics* / Q000473:pathology; D008579:Meningioma / Q000737:chemistry* / Q000235:genetics* / Q000473:pathology; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D051059:PTEN Phosphohydrolase / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D050800:STAT6 Transcription Factor / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D014746:Vimentin / Q000032:analysis
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D019941:Cyclin-Dependent Kinase Inhibitor p16; D066246:ErbB Receptors; D051059:PTEN Phosphohydrolase; D019253:Proto-Oncogene Proteins c-bcl-2; D018719:Erb-b2 Receptor Tyrosine Kinases; D050800:STAT6 Transcription Factor; D016159:Tumor Suppressor Protein p53; D014746:Vimentin; C061828:CD99 protein, human; C494101:STAT6 protein, human; C512478:EGFR protein, human; C508053:ERBB2 protein, human; C494929:PTEN protein, human