title: Imaging findings of extrapulmonary metastases of osteosarcoma.
abstract: OBJECTIVE
  To review imaging findings of extrapulmonary metastasis from osteosarcoma and to evaluate them for any consistent pattern and correlation between imaging findings.
  
  
  METHODS
  This study was retrospectively conducted in 13 patients with extrapulmonary metastasis of pathologically confirmed osteosarcoma. We evaluated the radioisotope (RI) scans (n=16), ultrasonography (USG) (n=4), computed tomography (CT) scans (n=10), MRIs (n=6), clinical records, and pathological reports for assessment of imaging findings and correlation between radiologic findings and RI uptake of the lesions. Points evaluated were the following: uptake on RI scans, presence of mineralization on CT, and MRI, size, enhancement pattern, attenuation on CT, signal intensity (SI) on MRI, and echogenicity on USG.
  
  
  RESULTS
  Extrapulmonary metastatic sites were diverse, including another bone other than the primary site (n=6), lymph node (n=4), pleura (n=2), liver (n=2), pancreas (n=1), kidney (n=1), peritoneum (n=1), muscle (n=1), and subcutaneous fat layer (n=1). One patient had tumor growth within the pulmonary artery and jejunum. Among 21 metastatic sites in 13 patients, bone scan was performed in 16 cases and RI uptake was detected in 10 lesions. Calcification was detected in eight lesions on radiologic imaging, including plain radiography, USG, CT, and MRI. Two lesions showed RI uptake without definite calcification or ossification on MRI and plain radiography, respectively. We analyzed the enhancement pattern and mass size in 18 metastatic sites and these factors had poor correlation with uptake on RI scans.
  
  
  CONCLUSIONS
  The sites and imaging findings of extrapulmonary metastasis of osteosarcoma were variable. All the lesions with mineralization were detectable on RI scans prior to radiologic imaging. RI scan has a limited role in the evaluation of metastatic lesions without mineralization.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine and Institute of Radiation Medicine, Seoul, Korea.
authors.forename: Seung Ja
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Choi
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Ja Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Hong
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Chung
authors.forename: Heung Sik
authors.initials: HS
authors.lastname: Kang
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000473:pathology*; D002648:Child; D003952:Diagnostic Imaging; D005260:Female; D006801:Humans; D007580:Jejunal Neoplasms / Q000556:secondary; D007680:Kidney Neoplasms / Q000556:secondary; D008113:Liver Neoplasms / Q000556:secondary; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000556:secondary; D012516:Osteosarcoma / Q000000981:diagnostic imaging / Q000556:secondary*; D010190:Pancreatic Neoplasms / Q000556:secondary; D010534:Peritoneal Neoplasms / Q000556:secondary; D010997:Pleural Neoplasms / Q000556:secondary; D011651:Pulmonary Artery / Q000473:pathology; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000556:secondary; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D019043:Vascular Neoplasms / Q000556:secondary