Week 3 Radiologic Approach to Bone Tumors

Question 1

What type of imaging is best used for diagnosis of bone tumors? Evaluation?

Answer 1

• diagnosis: radiograph (x rays)

- eval: MRI, CT, PET, scintigraphy

Question 2

Which brain tumors have a predilection for a specific age group?

Answer 2

• bone cysts, Ewing sarcoma tend to be in younger patients

- Metastatic lesions, myeloma, and conventional chondrosarcoma tend to be >40 years old

Question 3

How do number of lesions affect the diagnoses of bone tumors?

Answer 3

• benign can involve multiple sites
• primary malignancies rarely multifocal
• multiple malignant lesions: metastatic, MM, lymphoma

Question 4

What are 3 basic patterns of bone destruction and what growth rate do they reflect?

Answer 4

1. geographic (type 1):
   - complete bone destruction of one area. Slow, more likely to be benign
2. Moth eaten (type II): multiple clustered foci of bony destruction, aggressive
3. permeative (type III): multiple ill-defined foci of bone destruction, agressive
   - eg. Ewing

Question 5

What are different types of borders of lesions and what do they tell us?

Answer 5

-borders aka margins aka zone of transition
-only applies to lytic or predominantly lytic lesions, not for MRI
Geographic bone destruction
-IA: sharp demarcation, sclerosis. less agressive
-IB margin: sharp demarcation, no sclerosis
-IC margin: Ill defined region, either the entire circumference or only a portion of it

Question 6

How does the site of lesion influence diagnosis of bone tumor?

Answer 6

• some tumors are in specific bones/sties
• e.g. parosteal osteosarcoma: posterior aspect of distal femur
• chondroblastoma: preferes epiphysis or apophysis of long bones
• adamantinoma and osteofibrous dysplasia prefers tibia

Question 7

How does periosteal reaction on radiograph reflect malignancy of bone tumor?

Answer 7

1. Uninterrupted: solid smooth or elliptical layer, single lamellar reaction
   - indolent, benign process
2. onion-skin, lamellated
   - intermediate aggressive process
   - on that waxes and wanes
   - bone continually tries to wall off tumor
3. Sunburst, hair on end
   - most aggressive types
4. Codman’s triangle
   - elevation of periosteum away from the cortex
   - osteosarcoma, subperiosteal hematoma

Question 8

What clues does mineralization of osteoid give to ddx of bone tumors?

Answer 8

• rings and arcs: enchondroma, chondroblastoma, or chondrosarcoma
• easier to see on CT

Question 9

T/F presence of soft tissue mass generally suggests a benign process.

Answer 9

False, generally suggests malignant process. Except giant cell tumor.

Question 10

What should you do with a patient with an impending pathologic fracture?

Answer 10

• should be non weight bearing

- will have bette outcomes