title: Computed tomography imaging of anterior and middle mediastinal Ewing sarcoma/primitive neuroectodermal tumors.
abstract: OBJECTIVE
  We describe the computed tomography (CT) imaging features of Ewing sarcoma (EWS)/primitive neuroectodermal tumors (PNETs) arising in the anterior and middle mediastinum.
  
  
  METHODS
  The CT imaging findings of 6 cases of anterior and middle mediastinal EWS/PNETs were reviewed retrospectively. All 6 patients were examined with chest radiographs and CT, and 4 patients underwent isotope bone scans.
  
  
  RESULTS
  The average patient age was 40 years. Results using unenhanced CT showed lobulated, heterogeneous masses with patchy, necrotic foci in 5 cases, and one small, oval homogenous mass in the sixth case. There was no calcification in any of the cases. The contrast-enhanced CT results demonstrated that there were 4 cases of heterogeneous enhancement and one case of homogeneous enhancement. All the masses were ill-defined, and in 4 cases, the masses were displaced and encompassed the adjacent great vessels. The tumors directly infiltrated the anterior chest wall in 3 cases, and in one of these cases had eroded the sternum. Four cases demonstrated pleural effusions. Isotope bone scans showed distant bone metastases at diagnosis in 2 cases.
  
  
  CONCLUSIONS
  EWS/PNETs in the anterior and middle mediastinum appear as ill-defined, heterogenerous masses that are not distinguishable from other, more common, causes of mediastinal masses, based on their CT features.
authors.affiliation: State Key Laboratory of Oncology, South China, Guangdong 510060, PR China.
authors.forename: Wei-dong
authors.initials: WD
authors.lastname: Zhang
authors.forename: Ling-ling
authors.initials: LL
authors.lastname: Zhao
authors.forename: Xiao-bo
authors.initials: XB
authors.lastname: Huang
authors.forename: Pei-qiang
authors.initials: PQ
authors.lastname: Cai
authors.forename: Gui-xiao
authors.initials: GX
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D001707:Biopsy, Needle; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008479:Mediastinal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D018242:Neuroectodermal Tumors, Primitive / Q000000981:diagnostic imaging* / Q000473:pathology; D011857:Radiographic Image Interpretation, Computer-Assisted; D015641:Radiography, Interventional; D013902:Radiography, Thoracic; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012512:Sarcoma, Ewing / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide