title: Infarct-Associated Bone Sarcomas: Multimodality Imaging Findings.
abstract: OBJECTIVE
  The objective of our study was to characterize infarct-associated bone sarcoma and its imaging features.
  
  
  METHODS
  Our databases were searched for instances of sarcoma arising in association with osteonecrosis. Demographic and imaging data were recorded. The imaging studies of 258 patients with sarcomas were reviewed to determine whether underlying osteonecrosis was present. Radiographic and MRI studies of patients with bone infarction were reviewed to categorize the various appearances of infarction and to determine if sarcomas tended to arise in a particular pattern. A literature review was performed.
  
  
  RESULTS
  Nine infarct-associated bone sarcomas were found in eight patients: seven malignant fibrous histiocytomas (MFHs) and two osteosarcomas. All occurred in the femur or tibia; multifocal infarction was documented in all patients except one. Sarcomas were commonly associated with a so-called "mature"-type pattern of osteonecrosis-that is, with well-defined calcified margins. Osteolysis of infarct-associated MFHs was often overlooked at initial presentation and was often detected only after pathologic fracture. CT and MRI revealed cortical penetration in all cases; infarct margin disruption was evident, but preservation of fat within the infarct was typical. Increased radiotracer activity with relative central photopenia was characteristic of large infarct-associated bone sarcomas on scintigraphy. All lesions, including those treated at our institution and those found in the literature, were metaphyseal or diaphyseal, and although epiphyseal extension of sarcoma from a metadiaphyseal infarct was common, no purely epiphyseal lesions were encountered.
  
  
  CONCLUSIONS
  Radiologists must remain vigilant for this rare occurrence, especially in patients with new pain in an area of known bone infarction.
authors.affiliation: 1 Department of Radiology, University of Chicago, 5841 S Maryland Ave, MC 2026, Chicago, IL 60637.
authors.forename: Gregory Scott
authors.initials: GS
authors.lastname: Stacy
authors.affiliation: 1 Department of Radiology, University of Chicago, 5841 S Maryland Ave, MC 2026, Chicago, IL 60637.
authors.forename: Ryan
authors.initials: R
authors.lastname: Lo
authors.affiliation: 2 Department of Pathology, University of Chicago, Chicago, IL.
authors.forename: Anthony
authors.initials: A
authors.lastname: Montag
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005269:Femur / Q000098:blood supply*; D006801:Humans; D007238:Infarction / Q000150:complications*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D010020:Osteonecrosis / Q000150:complications; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012509:Sarcoma / Q000175:diagnosis* / Q000209:etiology; D013977:Tibia / Q000098:blood supply*; D014057:Tomography, X-Ray Computed
keywords: MRI; malignant fibrous histiocytoma; osteonecrosis; osteosarcoma; sarcoma