title: MRI and CT of Low-Grade Fibromyxoid Sarcoma in Children: A Report From Children's Oncology Group Study ARST0332.
abstract: OBJECTIVE
  The purpose of this article is to determine the MRI and CT features of low-grade fibromyxoid sarcoma in children.
  
  
  METHODS
  We retrospectively analyzed images of 11 pediatric patients with low-grade fibromyxoid sarcoma from a phase 3 clinical trial of nonrhabdomyosarcoma soft-tissue sarcoma (Children's Oncology Group Protocol ARST0332). MRI and CT were performed in 10 and four patients, respectively. Location, size, margin, and composition on imaging were correlated with pathologic findings.
  
  
  RESULTS
  Tumors were located in the extremities in nine patients, and one tumor each was located in the tongue and lung. Tumors were deep in seven patients and superficial in four patients. All tumors were well defined, solitary, and nonmetastatic at presentation. Tumors were complex solid-cystic in eight patients and completely solid in three patients. On T1-weighted images, all tumors had at least some areas hypointense to muscles, and six had a split-fat sign. On STIR or T2-weighted images, eight tumors had areas hypointense to adjacent muscle, and eight tumors had fluid signal intensity. On contrast-enhanced MRI studies, eight tumors had thick enhancing internal septations, and three had peripheral nodular gyriform enhancement. When we correlated imaging to pathologic findings, areas with hypointense signal intensity on both T1- and T2-weighted images were likely related to fibrous component; areas with fluid signal intensity on T2-weighted images were likely related to myxoid component. On CT, all four tumors were hypodense to muscle, and one tumor showed punctate calcific foci.
  
  
  CONCLUSIONS
  Low-grade fibromyxoid sarcoma is hypodense to muscle on CT. MRI may identify both fibrous and myxoid components of this rare pediatric soft-tissue sarcoma.
authors.affiliation: 1 Department of Radiology, University of Iowa College of Medicine, 200 Hawkins Dr, Iowa City, IA 52242.|2 Present address: Department of Radiology, Mallinckrodt Institute of Radiology, St Louis, MO.
authors.forename: Kiran
authors.initials: K
authors.lastname: Sargar
authors.affiliation: 1 Department of Radiology, University of Iowa College of Medicine, 200 Hawkins Dr, Iowa City, IA 52242.
authors.forename: Simon C
authors.initials: SC
authors.lastname: Kao
authors.affiliation: 3 Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA.
authors.forename: Sheri L
authors.initials: SL
authors.lastname: Spunt
authors.affiliation: 4 Department of Pediatrics, Seattle Children's Hospital, Seattle, WA.
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Hawkins
authors.affiliation: 5 Department of Pathology and Laboratory Medicine, Children's Hospital of Los Angeles and University of Southern California, Keck School of Medicine, Los Angeles, CA.
authors.forename: David M
authors.initials: DM
authors.lastname: Parham
authors.affiliation: 6 Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Coffin
authors.affiliation: 7 Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN.
authors.forename: M Beth
authors.initials: MB
authors.lastname: McCarville
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D005350:Fibroma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D060787:Neoplasm Grading; D012189:Retrospective Studies; D012509:Sarcoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: ARST0332; CT; Children's Oncology Group; MRI; low-grade fibromyxoid sarcoma; pediatrics