title: Dedifferentiated liposarcoma of retroperitoneum: spectrum of imaging findings in 15 patients.
abstract: BACKGROUND
  Dedifferentiated liposarcoma is a high-grade nonlipogenic sarcoma that arises in the background of a preexisting well-differentiated liposarcoma. The purpose of this work is to evaluate the spectrum of radiologic appearance of retroperitoneal dedifferentiated liposarcoma with clinicopathologic features.
  
  
  METHODS
  Radiologic images and clinical histories of 15 patients with histologically verified retroperitoneal dedifferentiated liposarcoma were retrospectively studied. Patients included 11 men and 4 women, with mean age of 55.8 years (range, 36-74 years), and they underwent computed tomography (CT) (n=15) and magnetic resonance imaging (MRI) (n=5).
  
  
  RESULTS
  The mean size of the tumor was 22.6 cm with a range of 9.5-38 cm. Both CT and MRI showed well-circumscribed, large round, or lobulated retroperitoneal mass. The appearance of the tumor was classified as follows: Category I, nonfatty component within predominant fatty mass (n=5); Category II, focal fatty component within large nonfatty mass (n=6); Category III, well-defined fatty mass and well-defined nonfatty mass (n=1); Category IV, two masses with predominantly nonfatty component (n=3).
  
  
  CONCLUSIONS
  Retroperitoneal dedifferentiated liposarcomas present various spectra of imaging findings. While Categories I and III may suggest dedifferentiated liposarcoma, Categories II and IV may appear as other types of liposarcoma or other malignant retroperitoneal tumor.
authors.affiliation: Department of Radiology, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Sun Hwa
authors.initials: SH
authors.lastname: Hong
authors.forename: Kyeong Ah
authors.initials: KA
authors.lastname: Kim
authors.forename: Ok Hee
authors.initials: OH
authors.lastname: Woo
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Park
authors.forename: Chul Hwan
authors.initials: CH
authors.lastname: Kim
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Jae-Joon
authors.initials: JJ
authors.lastname: Chung
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Sung Eun
authors.initials: SE
authors.lastname: Rha
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008080:Liposarcoma / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012186:Retroperitoneal Neoplasms / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*