title: Myxofibrosarcoma: prevalence and diagnostic value of the "tail sign" on magnetic resonance imaging.
abstract: OBJECTIVE
  Myxofibrosarcoma frequently shows curvilinear extensions of high T2 signal that also enhance on magnetic resonance imaging; these "tails" represent fascial extension of tumor at histopathological examination. This study was performed to determine whether the tail sign is helpful in distinguishing myxofibrosarcoma from other myxoid-containing neoplasms.
  
  
  METHODS
  The study group consisted of 44 patients with pathologically proven myxofibrosarcoma; the control group consisted of 52 patients with a variety of other myxoid-predominant tumors. Three musculoskeletal radiologists independently evaluated T2-weighted (and/or short-tau inversion recovery) and post-contrast MR images for the presence of one or more enhancing, high-signal intensity, curvilinear projections from the primary mass. Sensitivity and specificity for the diagnosis of myxofibrosarcoma were calculated for each reader. Interobserver variability was assessed with kappa statistic and percentage agreement.
  
  
  RESULTS
  A tail sign was deemed present in 28, 30, and 34 cases of myxofibrosarcoma and in 11, 9, and 5 of the controls for the three readers respectively, yielding a sensitivity of 64-77 % and a specificity of 79-90 %. The interobserver agreement was moderate-to-substantial (kappa=0.626).
  
  
  CONCLUSIONS
  The tail sign at MRI is a moderately specific and sensitive sign for the diagnosis of myxofibrosarcoma relative to other myxoid-containing tumors.
authors: Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA. lefkowir@mskcc.org
authors: Robert A
authors: RA
authors: Lefkowitz
authors: Jonathan
authors: J
authors: Landa
authors: Sinchun
authors: S
authors: Hwang
authors: Emily C
authors: EC
authors: Zabor
authors: Chaya S
authors: CS
authors: Moskowitz
authors: Narasimhan P
authors: NP
authors: Agaram
authors: David M
authors: DM
authors: Panicek
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D005350:Fibroma / Q000453:epidemiology* / Q000473:pathology*; D005354:Fibrosarcoma / Q000453:epidemiology* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D015588:Observer Variation; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity