title: MRI characteristics associated with high-grade myxoid liposarcoma.
abstract: OBJECTIVE
  To identify magnetic resonance imaging (MRI) features differentiating high-grade (>5% round-cell component) from low-grade myxoid liposarcomas (LPS) (≤5% round-cell component).
  
  
  METHODS
  Informed consent was waived. Patients with myxoid LPS and MRI before biopsy, neoadjuvant therapy, and surgery were included retrospectively. High-grade components were recorded from histological specimens by a pathologist (24 years of experience). Images were evaluated by a senior radiologist (>12 years of experience) for tumour size, location, tissue layer, and MRI features (signal intensity, heterogeneity, margin, and perilesional characteristics). Descriptive statistics, Fisher's exact test to identify associations with a round-cell component, and multivariate logistic regression to identify independent predictors of high-grade tumours were used.
  
  
  RESULTS
  Thirty-one patients (16 women [mean 51.1 years; range 19-79 years] and 15 men [mean 45.5 years; range 18-95 years]) with myxoid LPS (23 low-grade, eight high-grade) were included. All high-grade lesions had lipid signal, a peritumoural capsule and peritumoural contrast enhancement, and more commonly exhibited heterogeneous signal; however, the average size of ≥10 cm was the strongest independent indicator of high-grade status (odds ratio [OR], 14.6; 95% confidence interval [CI]: 1.6, 131).
  
  
  CONCLUSIONS
  Size ≥10 cm is most strongly associated with high-grade myxoid LPS (round-cell component >5%). Other features possibly differentiating high-grade from low-grade status include lesion margin, lipid signal, and perilesional characteristics.
authors.affiliation: Department of Medical Imaging, The University of Arizona, College of Medicine, Banner - University Medical Center, 1501 N Campbell Ave., P.O. Box 245067, Tucson, AZ 85724, USA. Electronic address: lgimber@radiology.arizona.edu.
authors.forename: L H
authors.initials: LH
authors.lastname: Gimber
authors.affiliation: Department of Pathology, The Johns Hopkins University, Weinberg Bldg, Rm. 2242, 401 North Broadway, Baltimore, MD 21231, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Montgomery
authors.affiliation: Department of Orthopaedic Surgery, Johns Hopkins Medicine, 601 N Caroline St, Baltimore, MD 21287, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Morris
authors.affiliation: Department of Radiology & Imaging Sciences, Emory University, 1364 Clifton Rd NE D107, Atlanta, GA 30322, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Krupinski
authors.affiliation: The Russell H. Morgan Department of Radiology & Radiological Science, The Johns Hopkins University School of Medicine, 601 North Wolfe Street, Baltimore, MD 21287, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Fayad
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D018208:Liposarcoma, Myxoid / Q000000981:diagnostic imaging* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D012189:Retrospective Studies; D055815:Young Adult