title: Undifferentiated (embryonal) sarcoma of the liver: pathologic basis of imaging findings in 28 cases.
abstract: OBJECTIVE
  To correlate the imaging and pathologic features of undifferentiated (embryonal) sarcoma (UES) and account for the discrepancy between the solid appearance at ultrasound (US) and the almost cystlike appearance at computed tomography (CT) and magnetic resonance (MR) imaging.
  
  
  METHODS
  The clinical, pathologic, and imaging findings in 28 patients (age range, 3-49 years) with pathologically proved UES were retrospectively reviewed. All patients underwent at least one cross-sectional imaging study to include CT (27 patients), US (21 patients), and MR imaging (six patients). Tumor size, gross morphology (n = 27), histologic features, and proportion of solid and cystlike components were evaluated and correlated to the imaging findings.
  
  
  RESULTS
  The mean transverse diameter of the tumors was 14 cm (range, 10-25 cm). At gross examination, the tumors were predominantly solid (mean, 83% of tumor volume), and pathologic and US findings were concordant. Conversely, CT scans showed low attenuation (approximately that of water) in 88% of the tumor volume and T2-weighted MR images showed high signal intensity (approximately equal to that of cerebrospinal fluid) in 89% of the tumor volume.
  
  
  CONCLUSIONS
  UES shows a misleading cystlike appearance at CT and MR imaging compared with US and pathologic findings. In a child or young adult with a liver tumor, this finding is useful in making a prospective diagnosis and avoiding misguided attempts at drainage.
authors.affiliation: Department of Radiologic Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
authors.forename: P C
authors.initials: PC
authors.lastname: Buetow
authors.forename: J L
authors.initials: JL
authors.lastname: Buck
authors.forename: L
authors.initials: L
authors.lastname: Pantongrag-Brown
authors.forename: W H
authors.initials: WH
authors.lastname: Marshall
authors.forename: P R
authors.initials: PR
authors.lastname: Ros
authors.forename: M S
authors.initials: MS
authors.lastname: Levine
authors.forename: Z D
authors.initials: ZD
authors.lastname: Goodman
mesh_terms: D000293:Adolescent; D000328:Adult; D001834:Body Water; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D003560:Cysts; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging; D004322:Drainage; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D008113:Liver Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009373:Neoplasms, Germ Cell and Embryonal / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D011856:Radiographic Image Enhancement; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D005682:Gadolinium