title: MR imaging differentiation of benign and malignant peripheral nerve sheath tumors: use of the target sign.
abstract: BACKGROUND
  T2-weighted MR imaging of soft tissue tumors of neural origin may show round lesions with a central hypointensity and a hyperintense rim resembling a target. We define the "target sign" as a mass consisting of a solitary target, or a multicompartmental mass in which the largest component consists of multiple targets.
  
  
  OBJECTIVE
  The objective of this study was to determine whether the target sign can differentiate benign neurofibromas and their malignant counterparts, malignant peripheral nerve sheath tumors. Materials and methods. Preoperative T2-weighted MR images of 23 neurofibromas or malignant peripheral nerve sheath tumors were retrospectively reviewed in 16 patients, aged 3 weeks to 20 years (median 15 years), without knowledge of the pathologic diagnosis. The presence or absence of a target sign was noted.
  
  
  RESULTS
  The target sign was seen in all 12 neurofibromas and 1 of the 11 malignant peripheral nerve sheath tumors. Statistical analysis showed good differentiation of benign and malignant tumors using this sign (chi = 0.91).
  
  
  CONCLUSIONS
  The target sign on T2-weighted MR imaging is helpful in differentiating neurofibromas from malignant peripheral nerve sheath tumors.
authors.affiliation: Department of Diagnostic Imaging, St. Jude Children's Research Hospital, 332 N. Lauderdale St., Memphis, TN 38101, USA.
authors.forename: R
authors.initials: R
authors.lastname: Bhargava
authors.forename: D M
authors.initials: DM
authors.lastname: Parham
authors.forename: O E
authors.initials: OE
authors.lastname: Lasater
authors.forename: R S
authors.initials: RS
authors.lastname: Chari
authors.forename: G
authors.initials: G
authors.lastname: Chen
authors.forename: B D
authors.initials: BD
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008938:Mitosis; D009336:Necrosis; D018317:Nerve Sheath Neoplasms / Q000175:diagnosis* / Q000473:pathology; D009455:Neurofibroma / Q000175:diagnosis / Q000473:pathology; D009456:Neurofibromatosis 1 / Q000175:diagnosis / Q000473:pathology; D010524:Peripheral Nervous System Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies