title: Sonographic Differentiation Between Schwannomas and Neurofibromas in the Musculoskeletal System.
abstract: OBJECTIVE
  The purpose of this study was to determine key features and define a strategy for differentiation between schwannomas and neurofibromas using sonography.
  
  
  METHODS
  This retrospective study was approved by the Institutional Review Board at our hospital, and informed consent was waived. We reviewed sonograms of pathologically proven schwannomas and neurofibromas of the extremities and body wall. On grayscale images, tumors were evaluated on the basis of their size, maximum-to-minimum diameter ratio, shape, contour, margin, location, encapsulation, echogenicity, echo texture, cystic changes, presence of intratumoral calcifications, presence of a target sign, and presence of an entering or exiting nerve. If an entering or exiting nerve was identified, the nerve-tumor position and nerve-tumor transition were characterized. On color Doppler images, the presence and amount of vascularity were evaluated. Student t tests were used for analysis of continuous variables (size, maximum-to-minimum diameter ratio, and age); χ(2) and Fisher exact tests were used for analysis of categorical variables.
  
  
  RESULTS
  A total of 146 pathologically proven tumors, including 115 schwannomas and 31 neurofibromas of the extremities and body wall, were included. The maximum diameter, maximum-to-minimum diameter ratio, contour, cystic portion, nerve-tumor position, nerve-tumor transition, and vascularity were significantly different in schwannomas versus neurofibromas (P < .05), and a lobulated contour, fusiform shape, and hypovascularity of neurofibromas could be helpful for differentiation when a prediction model is considered. The nerve-tumor position, nerve-tumor transition, and maximum-to-minimum diameter ratio were also significantly different between groups (P < .05) and thus could be useful for differentiation of neurogenic tumors.
  
  
  CONCLUSIONS
  Sonographic findings are helpful in differentiating between schwannomas and neurofibromas.
authors.affiliation: Departments of Radiology (J.A.R.) and Internal Medicine (T.Y.K.), Hanyang University College of Medicine, Guri Hospital, Seoul, Korea; and Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea (S.H.L., E.-Y.C., S.M.K., M.J.S.).
authors.forename: Jeong Ah
authors.initials: JA
authors.lastname: Ryu
authors.affiliation: Departments of Radiology (J.A.R.) and Internal Medicine (T.Y.K.), Hanyang University College of Medicine, Guri Hospital, Seoul, Korea; and Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea (S.H.L., E.-Y.C., S.M.K., M.J.S.). shlee@amc.seoul.kr.
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Departments of Radiology (J.A.R.) and Internal Medicine (T.Y.K.), Hanyang University College of Medicine, Guri Hospital, Seoul, Korea; and Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea (S.H.L., E.-Y.C., S.M.K., M.J.S.).
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Cha
authors.affiliation: Departments of Radiology (J.A.R.) and Internal Medicine (T.Y.K.), Hanyang University College of Medicine, Guri Hospital, Seoul, Korea; and Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea (S.H.L., E.-Y.C., S.M.K., M.J.S.).
authors.forename: Tae Yeob
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Departments of Radiology (J.A.R.) and Internal Medicine (T.Y.K.), Hanyang University College of Medicine, Guri Hospital, Seoul, Korea; and Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea (S.H.L., E.-Y.C., S.M.K., M.J.S.).
authors.forename: Sung Moon
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Departments of Radiology (J.A.R.) and Internal Medicine (T.Y.K.), Hanyang University College of Medicine, Guri Hospital, Seoul, Korea; and Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea (S.H.L., E.-Y.C., S.M.K., M.J.S.).
authors.forename: Myung Jin
authors.initials: MJ
authors.lastname: Shin
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000000981:diagnostic imaging*; D009442:Neurilemmoma / Q000000981:diagnostic imaging*; D009455:Neurofibroma / Q000000981:diagnostic imaging*; D010524:Peripheral Nervous System Neoplasms / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
keywords: musculoskeletal ultrasound; neurofibroma; schwannoma; soft tissue tumor