Primary Bone Neoplasms

Primary Bone Neoplasms

Todd M. Blodgett, MD

Alex Ryan, MD

Joanna Costello, MD

Graphic shows the typical appearance of a primary sarcoma of the femur image.

Coronal graphic shows the typical appearance of a mandibular osteosarcoma image.


Abbreviations and Synonyms

  • Chondrosarcoma

  • Ewing sarcoma

  • Osteogenic sarcoma, osteosarcoma, primary bone sarcoma


  • Chondrosarcoma

    • Primary malignant tumor of bone

    • Produces hyaline cartilage leading to abnormal cartilage &/or bone

  • Ewing sarcoma

    • Primary malignant tumor of bone

  • Osteosarcoma

    • Primary malignant tumor of bone

    • Contains osteoid with osteoblastic differentiation


General Features

  • Best diagnostic clue

    • Chondrosarcoma

      • Mass with variable chondroid matrix

      • May have cortical disruption &/or soft tissue extension

      • FDG uptake tends to correlate with tumor grade

    • Ewing sarcoma

      • Permeative appearance ± extraosseous large soft tissue component adjacent to bone

    • Osteosarcoma

      • Heterogeneous metaphyseal mass

      • Increased FDG uptake with high grade osteosarcoma

      • May have characteristic starburst appearance

  • Location

    • Chondrosarcoma

      • Most common areas: Pelvis, femur, and humerus

      • Mostly in proximal aspect of long bones

      • Peripheral, periosteal, or central intraosseous locations

    • Ewing sarcoma

      • Most common in metaphysis or diaphysis of long bones

      • May arise in any bone

    • Osteosarcoma

      • Metaphyseal long bone

      • Distal femur

  • Size: Variable

  • Morphology

    • Ewing sarcoma

      • Obscured margins

      • Aggressive periosteal invasion

    • Osteosarcoma

      • Bone mass with destruction of bone elements

      • Cortical expansion

      • Large zone of transition

    • Chondrosarcoma

      • Endosteal scalloping

      • May have cortical destruction

      • Typically associated with a large soft tissue mass

Imaging Recommendations

  • Best imaging tool

    • FDG PET and PET/CT may be useful for staging, restaging, and response to therapy

      • Both have current insurance coverage limitations

CT Findings

  • Chondrosarcoma

    • Lytic mass with medullary cavity expansion

    • Variable amounts of calcification and chondroid matrix

    • Often have cortical thickening

    • ± Soft tissue mass

    • ± Endosteal scalloping

  • Ewing sarcoma

    • Commonly involves long bones (metaphysis or diaphysis)

    • Intramedullary mass ± involvement of the cortex

      • Permeative/“moth-eaten” appearance

      • Heterogeneous contrast enhancement

    • Periosteal reaction often described as “sunburst”

      • Large zone of transition

    • Soft tissue mass frequently present

    • Frequently metastasizes to lung, bone, and marrow

  • Osteosarcoma

    • Intramedullary mass

    • “Moth-eaten” appearance of osseous destruction

    • Indistinct borders

    • Wide zone of transition

    • Cortical break through

    • Most common in distal femur

    • Sunburst pattern of periosteal reaction

    • May have contrast enhancement

Nuclear Medicine Findings

  • Initial diagnosis

    • High grade tumors typically have intense FDG activity

    • FDG PET is sensitive for osteosarcoma and Ewing sarcoma

    • Chondrosarcoma shown to have low FDG uptake (average SUV of 4.5)

    • Histologic grade correlates well with SUV between high and low grade bone sarcomas

  • Staging

    • PET/CT improves accuracy of identification and localization of invasive disease

      • Crucial for determining approach to therapy

      • Invasion of adjacent structures can be determined

      • FDG PET superior for detection of osseous lesions

      • Useful for estimating percentage of tumor necrosis

      • PET/CT may offer additional biopsy localization information

      • CT more sensitive for lung lesions

    • Ewing sarcoma

      • Tend to be FDG avid

      • Small study reported overall sensitivity 96% and specificity 78%

      • PET/CT more sensitive than bone scan for osseous metastases

      • Degree of FDG uptake indicates disease stage and may have prognostic value

    • Chondrosarcoma

      • Low FDG uptake and metabolic activity in cartilaginous tissue

      • FDG uptake increases with more aggressive histologic tumor types

      • Cannot differentiate grade I chondrosarcoma from benign cartilage tumors

      • High pre-treatment SUV sensitive for higher grade tumor

      • High sensitivity for high grade mets

      • SUV may be as accurate as tumor grade for prognosis of overall survival

  • Restaging

    • PET/CT superior to CT alone for

      • Detection of minimal malignant residue

      • Distinction between vital and necrotic tumor regions

      • Improved detection and localization of recurrence in patients with implanted orthopedic devices

  • Response to therapy

Sep 22, 2016 | Posted by in MAGNETIC RESONANCE IMAGING | Comments Off on Primary Bone Neoplasms

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