title: Primitive neuroectodermal tumor of the orbit in a 5-year-old girl with microphthalmia.
abstract: OBJECTIVE
  To report an orbital, intraconal, primitive neuroectodermal tumor (PNET) in a 5-year-old child with microphthalmia since birth.
  
  
  METHODS
  Orbitotomy was performed and a large, polycystic, retroscleral, intraconal tumor was removed and subsequent histological, immunohistochemical and electron-microscopic analyses of the excised mass were performed.
  
  
  RESULTS
  The tumor showed characteristic features of peripheral primitive neuroectodermal tumor including pseudorosettes, positive immunohistochemical reactions for the MIC2 gene and synaptophysin and ultrastructural finding of neurosecretory granules.
  
  
  CONCLUSIONS
  This case is the first reported intraconal PNET of the orbit, and the first orbital case that expresses the MIC2 gene. In spite of the aggressive malignant features of peripheral PNET, the orbital variety seems to be the least aggressive since most of the reported patients are still alive.
authors.affiliation: Eye Pathology Institute, University of Copenhagen, Denmark.
authors.forename: G A
authors.initials: GA
authors.lastname: Alyahya
authors.forename: S
authors.initials: S
authors.lastname: Heegaard
authors.forename: H C
authors.initials: HC
authors.lastname: Fledelius
authors.forename: C
authors.initials: C
authors.lastname: Rechnitzer
authors.forename: J U
authors.initials: JU
authors.lastname: Prause
mesh_terms: D001706:Biopsy; D002675:Child, Preschool; D003131:Combined Modality Therapy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008850:Microphthalmos / Q000150:complications*; D018242:Neuroectodermal Tumors, Primitive / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D009918:Orbital Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D014057:Tomography, X-Ray Computed