title: Intramedullary chondroid tumors of bone: correlation of abnormal peritumoral marrow and soft-tissue MRI signal with tumor type.
abstract: OBJECTIVE
  To determine whether enchondromas and chondrosarcomas can be differentiated on the basis of peritumoral MR signal abnormality.
  
  
  METHODS
  STIR and T2-weighted MRI images were retrospectively assessed for the presence and extent of abnormal peritumoral marrow and soft-tissue signal. The cause of the peritumoral signal abnormality was determined by histologic correlation with resection specimens. The presence or absence of bone destruction was noted.
  
  
  METHODS
  Twenty-three patients were studied: ten with enchondromas (three men, seven women; ages 33-73 years) and 13 with chondrosarcomas (seven men, six women; ages 25-88 years).
  
  
  RESULTS
  Abnormal peritumoral marrow signal was present on STIR images around none of 10 enchondromas and all of 13 chondrosarcomas (P < 0.0001). The marrow signal abnormality corresponded histologically to fine marrow fibrosis in all cases. Adjacent abnormal soft-tissue signal was present on STIR images around none of ten enchondromas and eight (62%) of 13 chondrosarcomas (P = 0.0026). Abnormal soft-tissue signal was more common around high-grade than low-grade chondrosarcomas (100% vs 38%, P = 0.028), and was more extensive (mean extent 28 mm vs 8 mm; P > 0.04). In the subset of tumors without bone destruction, peritumoral marrow signal abnormality was present around none of ten enchondromas and all of five chondrosarcomas (P = 0.0003); abnormal soft-tissue signal was present around none of ten enchondromas and two of five chondrosarcomas (P > 0.05).
  
  
  CONCLUSIONS
  Abnormal marrow or soft-tissue signal around a chondroid tumor is suggestive of chondrosarcoma, even in the absence of bone destruction. STIR images are necessary for adequate detection of peritumoral signal abnormalities.
authors.affiliation: Department of Radiology, Vancouver Hospital and Health Sciences Center, BC, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Janzen
authors.forename: P M
authors.initials: PM
authors.lastname: Logan
authors.forename: J X
authors.initials: JX
authors.lastname: O'Connell
authors.forename: D G
authors.initials: DG
authors.lastname: Connell
authors.forename: P L
authors.initials: PL
authors.lastname: Munk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000473:pathology* / Q000601:surgery; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000601:surgery; D002812:Chondroma / Q000175:diagnosis* / Q000601:surgery; D002813:Chondrosarcoma / Q000175:diagnosis* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010521:Periosteum / Q000473:pathology* / Q000601:surgery