title: MR imaging for preoperative diagnosis and assessment of local tumor extent on localized giant cell tumor of tendon sheath.
abstract: OBJECTIVE
  The purpose of this study was to clarify the usefulness of MR imaging for preoperative diagnosis and evaluation of the extent of localized giant cell tumor of tendon sheath (GCTTS).
  
  
  METHODS
  We retrospectively reviewed the MR images of 25 patients with surgically proved GCTTS (seven males and 18 females; mean age, 41 years) including five recurrences. T1- and T2-weighted imaging was carried out on 24 and 22 lesions, respectively. Gadolinium-enhanced images were obtained for 20 lesions. We evaluated the tumor extent around the phalanx (the degree of circumferential occupation by a tumor around the phalanx on an axial plane) and involvement of the bone, joint, and tenosynovial space by both MR imaging and surgery (gold standard).
  
  
  RESULTS
  MR signal intensities of the GCTTSs were consistently equal to those of skeletal muscle or between those of muscle and fat on T1-weighted images; on T2-weighted images, the signal intensities tended to be between those of muscle and fat. Most lesions were inhomogeneous due to low-signal-intensity areas, and enhanced following gadolinium administration. The tumor extent around the phalanx was 168.5 +/- 99.2 degrees (63-360 degrees). MR imaging did not identify the bone involvement (five lesions), but depicted the involvement of the joint in four of five lesions and the tenosynovial space in nine of ten lesions.
  
  
  CONCLUSIONS
  This study confirms that MR imaging is able to depict the characteristic internal signal of GCTTS. Moreover, it can accurately assess the tumor size and degree of extent around the phalanx, which can affect the type of surgical approach.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D005384:Finger Joint / Q000473:pathology*; D005870:Giant Cell Tumors / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000175:diagnosis* / Q000601:surgery; D011300:Preoperative Care; D012189:Retrospective Studies; D013710:Tendons / Q000473:pathology*