title: MR findings indicative of hemosiderin in giant-cell tumor of bone: frequency, cause, and diagnostic significance.
abstract: OBJECTIVE
  We studied the frequency, cause, and diagnostic significance of MR findings indicative of large amounts of hemosiderin in giant-cell tumor of bone.
  
  
  METHODS
  The clinical, MR, and histologic findings in 16 patients with giant-cell tumors of bone were reviewed. Eight tumors occurred in uncommon locations or in patients who were not in the usual age range; the other eight were more typical. Areas of decreased MR signal intensity considered to be caused by hemosiderin were identified. The number and distribution of RBCs within the tumor were studied histologically, and the presence of hemosiderin was determined on histologic sections made with iron stains.
  
  
  RESULTS
  In 10 cases in which MR images showed areas of low signal intensity, large amounts of hemosiderin were noted histologically. The low-signal-intensity areas were nodular, zonal, whorled, or diffuse and occupied at least one fifth of the tumor volume. On histologic examination, many erythrocytes were in direct contact with the tumor cells, and the hemosiderin was seen in both mononuclear and multinuclear tumor cells.
  
  
  CONCLUSIONS
  Hemosiderin is commonly seen on MR images of giant-cell tumors of bone (63%) and is probably related to the extravasated erythrocytes in the tumor and the phagocytic function of the tumor cells. This MR finding supports the diagnosis, even in giant-cell tumors in uncommon locations or in patients who are not in the typical age range.
authors.affiliation: Department of Radiology, Shinshu University School of Medicine, Nagano, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Aoki
authors.forename: H
authors.initials: H
authors.lastname: Tanikawa
authors.forename: K
authors.initials: K
authors.lastname: Ishii
authors.forename: G S
authors.initials: GS
authors.lastname: Seo
authors.forename: O
authors.initials: O
authors.lastname: Karakida
authors.forename: S
authors.initials: S
authors.lastname: Sone
authors.forename: T
authors.initials: T
authors.lastname: Ichikawa
authors.forename: K
authors.initials: K
authors.lastname: Kachi
mesh_terms: D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000737:chemistry / Q000175:diagnosis*; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000737:chemistry / Q000175:diagnosis*; D006485:Hemosiderin / Q000032:analysis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged
chemical_list: D006485:Hemosiderin