title: Computerized tomography characteristics that differentiate angiomyolipomas from liposarcomas in the perinephric space.
abstract: OBJECTIVE
  We performed a retrospective study to determine computerized tomography (CT) findings associated with perinephric angiomyolipomas or perinephric liposarcomas.
  
  
  METHODS
  During the last 7 years 6 patients with perinephric angiomyolipoma and 12 with perinephric liposarcoma were seen at our hospital. Two radiologists who were blinded to the pathological diagnosis retrospectively evaluated the CT characteristics of perinephric angiomyolipoma and perinephric liposarcoma. The relationship of each CT characteristic with tumor type was compared using Fisher's exact test.
  
  
  RESULTS
  The CT characteristics of perinephric angiomyolipoma were intratumoral linear vascularity (p = 0.001), aneurysmal dilatation (p = 0.025), bridging vessel sign (p = 0.005), hematoma (p = 0.025), beak sign (p = 0.001) and discrete intrarenal fatty tumors (p = 0.025). The CT characteristic of perinephric liposarcoma was a nonfatty soft tissue mass (p = 0.005). There was no significant difference in the presence of calcifications in both groups.
  
  
  CONCLUSIONS
  This retrospective study suggests that analysis of CT characteristics (linear vascularity, aneurysmal dilatation, bridging vessel sign, hematoma, beak sign and discrete intrarenal fatty tumors) may help to differentiate perinephric angiomyolipoma from perinephric liposarcoma.
authors.affiliation: Department of Diagnostic Radiology, Chang Gung Memorial Hospital and Biostatistics Center, Chang Gung University, Taipei, Taiwan.
authors.forename: Li-Jen
authors.initials: LJ
authors.lastname: Wang
authors.forename: Yon-Cheong
authors.initials: YC
authors.lastname: Wong
authors.forename: Chi-Jen
authors.initials: CJ
authors.lastname: Chen
authors.forename: Lai-Chu
authors.initials: LC
authors.lastname: See
mesh_terms: D000328:Adult; D018207:Angiomyolipoma / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D008080:Liposarcoma / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed