3b. Osteosarcoma (Primary Neoplasms)

Question 1

What is an Osteosarcoma?

Answer 1

Undifferentiated connective tissue produces neoplastic osteoid

Question 2

What are the 5 clinical types of Osteosarcoma?

Answer 2

• Central Osteosarcoma
• Multicentric Osteosarcoma
• Parosteal Osteosarcoma
• Secondary Osteosarcoma
• Extraosseous Osteosarcoma

Question 3

At what age do osteosarcomas occur?

Answer 3

10-25

Question 4

Can Osteosarcomas occur in older patients?

Answer 4

Yes, likely due to malignant degeneration of a benign proces

Question 5

MC in male or females?

Answer 5

Males

Question 6

What percentage of primary malignancies of bones are Osteosarcoma’s?

Answer 6

20%

Question 7

Does trauma cause Osteosarcoma’s? (I know, dumb question)

Answer 7

No, but commonly it is what brings our attention to the area. Painful swelling is common.

Question 8

Do you normally see systemic signs with Osteosarcoms’s?

Answer 8

No, they are unusual; however fever is possible

Question 9

Pain pattern with Osteosarcoma?

Answer 9

Initially insidious and transitory; later becomes severe and persistent

Question 10

Usual length of time from onset of symptoms to diagnosis in patient’s with an Osteosarcoma?

Answer 10

Greater than 6 months

Question 11

75% of Osteosarcoma’s occur where?

Answer 11

Metaphysis of long bones (esp. distal femur, proximal tibia, and proximal humerus)

Question 12

Common appearance of ossification mass?

Answer 12

“Cumulus Cloud” appearance

Question 13

What type of cortical disruption is found?

Answer 13

Spiculated periosteal response, soft tissue mass

Question 14

What imaging is used to determine extent of lesion?

Answer 14

MRI (chest CT and bone scan to detect metastasis)

Question 15

Common metastasis for Osteosarcoma?

Answer 15

Lungs (called “cannonball mets”). Also mets to other bones is common.

Question 16

Treatment?

Answer 16

• Radiation
• Chemotherapy
• Resection; amputation

Question 17

Which type of lesions are more aggressive?

Answer 17

Purely lytic lesions

Question 18

Which type of Osteosarcoma is slower growing, but similar in sites and symptoms to central Osteosarcoma?

Answer 18

Parosteal Osteosarcoma (PO)

Question 19

Age range of PO?

Answer 19

30-50

Question 20

Does PO cause a periosteal response?

Answer 20

No

Question 21

What’s unique about PO?

Answer 21

It’s a dense, juxtacortical mass with stalk to cortex

Question 22

What would you Ddx Po against?

Answer 22

Myositis Ossificans

Question 23

Ddx features in PO vs. Myositis Ossificans

Answer 23

PO =

• Stalk attaches to cortex,
• central portion more dense; periphery less dense,
• grows over time

Myositis Ossificans =

• Seperated from bone,
• less dense centrally; periphery of denser cortical bone,
• smaller over time

Question 24

What is a Secondary Osteosarcoma?

Answer 24

Malignant degeneration of a benign lesion (paget’s disease, fibrous dysplasia, osteochondroma, enchondroma)