title: Peripheral primitive neuroectodermal tumors in adults: documentation by molecular analysis.
abstract: OBJECTIVE
  The Ewing tumor (ET) family of peripheral primitive neuroectodermal tumors (pPNETs) are primitive small round-cell tumors (SRCTs) of the bone and soft tissue that occur predominantly in children and adolescents. However, pPNETs only rarely enter the differential diagnosis of bone and soft tissue SRCTs in adults. Recently, gene fusions between the EWS gene and different members of the ETS transcription factor family have been shown to occur in virtually all pPNETs and thus constitute a pathognomonic marker for this tumor subclass. The aim of the present study was to document EWS/ETS fusion gene expression in suspected pPNETs of adults as objective evidence for the existence of this tumor family in older patients.
  
  
  METHODS
  The three contributing molecular diagnostic laboratories retrospectively compiled a cohort of all SRCT cases in which EWS/ETS gene fusions had been shown by molecular analysis. This cohort was surveyed for cases that occurred in patients aged 40 years or older, which were then analyzed for their clinical and pathologic features.
  
  
  RESULTS
  Nine patients between 40 and 65 years of age were found to have tumors positive for EWS/ETS gene fusions. Standard histopathologic and clinical features of these cases, other than age, were similar to those of childhood pPNETs. Patients were initiated on appropriate therapy after molecular analysis confirmed the diagnosis of pPNET.
  
  
  CONCLUSIONS
  Identification of an EWS/ETS gene fusion is useful in providing objective evidence of the diagnosis of pPNET in patients over the age of 40 years. This diagnosis should be considered in adults who present with bone and soft tissue SRCTs and appropriate biopsy specimens should be collected for molecular analysis at the time of diagnosis.
authors.affiliation: Department of Pathology, British Columbia's Children's Hospital, Vancouver, Canada.
authors.forename: E R
authors.initials: ER
authors.lastname: Lawlor
authors.forename: J A
authors.initials: JA
authors.lastname: Mathers
authors.forename: T
authors.initials: T
authors.lastname: Bainbridge
authors.forename: D E
authors.initials: DE
authors.lastname: Horsman
authors.forename: A
authors.initials: A
authors.lastname: Kawai
authors.forename: J H
authors.initials: JH
authors.lastname: Healey
authors.forename: A G
authors.initials: AG
authors.lastname: Huvos
authors.forename: J A
authors.initials: JA
authors.lastname: Bridge
authors.forename: M
authors.initials: M
authors.lastname: Ladanyi
authors.forename: P H
authors.initials: PH
authors.lastname: Sorensen
mesh_terms: D000328:Adult; D000368:Aged; D002869:Chromosome Aberrations; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D018242:Neuroectodermal Tumors, Primitive / Q000235:genetics* / Q000473:pathology; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000235:genetics* / Q000473:pathology; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D016133:Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D004273:DNA, Neoplasm; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors