Radiologic approach to bone tumors

Question 1

Role of the radiologist

Answer 1

• To work w/ orthopedic oncologist, pathologist to Dx and Rx the pt
• DDx of pathologist and radiologist may be identical

Question 2

T/F questions 1

Answer 2

• CT guided bone biopsy shouldn’t always be obtained thru most direct approach (can introduce tumor cells into new compartments)
• MRI isn’t the most useful in Dxing bone tumors (X-rays are)
• Xrays aren’t the most useful in revealing extent of disease (MRIs are)

Question 3

Ways to Dx bone tumors on xrays

Answer 3

• Most bone tumors have predilection for a specific age group
• Number of lesions
• Type of bone destruction
• Borders of the lesion

Question 4

Bone destruction/borders

Answer 4

• From least to most aggressive
• Type1 (geographic): complete bony destruction
• Type2 (moth eaten): multiple clustered foci of bone destruction
• Type3 (permeative, ewing sarcoma): multiple ill-defined foci of bony destruction

Question 5

Borders of lesions

Answer 5

• Blastic/sclerotic lesions are circumscribed
• Found on X-rays, not MRIs
• From least to most aggressive
• 1A margin: sharp demarcation + sclerosis
• 1B margin: sharp demarcation w/o sclerosis
• 1C margin: ill-defined region, interface w/ bone

Question 6

T/F questions 2

Answer 6

• Moth eaten pattern of bone destruction is aggressive
• Xrays are used to see the borders of lesions
• Geographic destruction pattern + sclerotic margin means not aggressive

Question 7

Sites of bone tumors

Answer 7

• Some tumors arise in specific bones and/or specific site of bones
• Chondroblastoma prefers the epiphysis of long bones (produces sclerotic rim)
• Adamantinoma and osteofibrous dysplasia: tibia

Question 8

Periosteal reactions

Answer 8

• Uninterrupted (continuous): cortical thickening, indicates benign process
• Lamellated (onion-skin): many layers of cortical thickening, indicated intermediate aggressive process (waxes and wanes)
• Interrupted (sunburst, frayed ends): most aggressive types
• Codman’s triangle: elevation of the periosteum away from cortex, very aggressive

Question 9

Matrix mineralization

Answer 9

• Types of mineralized (calcified) matrix indicates the tumor
• Osteoid: fluffy and cloud-like
• Chondroid: a bunch of clustered rings and arcs

Question 10

Soft tissue mass

Answer 10

• Soft tissue components suggest malignant process

- Ex: osteosarcoma, ewing sarcoma, lymphoma

Question 11

T/F questions 3

Answer 11

• Locations of lesion do help predict Dx
• Chondroid matrix mineralization is not fluffy and cloud-like, but many rings/arcs (osteoid matrix is fluffy and cloud-like)
• Sunburst periosteal rxn is very aggressive
• Presence of soft tissue masses suggests malignant process
• A pt w/ impending pathologic fracture should be non-weight bearing