1.2 Bone Tumors

Question 1

Osteoma

• where usually
• associated syndrome?

Answer 1

• benign tumor of bone
• common on facial bones
• associated with Gardner syndrome (FAP, Fibromatosus of retroperitoneum, Osteoma)

Question 2

Osteoid osteoma

Answer 2

• benign tumor of osteoblasts surrounded by rim of reactive bone
• presents as bony mass with osteoid core
• located in cortex of long bones

Question 3

Osteoblastoma vs Osteoid osteoma

• similarities
• differences (3 ways to distinguish)

Answer 3

• both are osteoblast tumors
  1. size: osteoblastoma is larger (>2cm vs <2cm)
  2. location: osteoblastoma–vertebrae, osteoid osteoma–long bones
  3. aspirin: Osteoblastoma does not respond to aspirin, Osteoid sarcoma does

Question 4

Osteosarcoma

• what is it
• location
• how does it present

Answer 4

• malignant tumor of osteoblasts
• metaphysis of long bones, usu near knee
• presents as fracture/bone pain, no swelling
• Codman triangle (lifting of periosteum)

Question 5

Codman’s triangle

Answer 5

• xray finding of osteosarcoma

- shows lifting of periosteum by tumor

Question 6

Osteochondroma

• what is it
• location

Answer 6

• benign bone tumor with cartilage cap

- arises from metaphysis (growth plate) lateral projection

Question 7

what is most common benign tumor of bone?

Answer 7

osteochondroma

Question 8

Giant Cell tumor

• what is it
• location
• clinical findings

Answer 8

• think ‘giant soap’
• tumor of multinucleated giant cells and stromal cells
• only tumor in epiphysis, usu near knee
• “soap bubbles” on xray

Question 9

Ewing sarcoma

• what is it
• location

Answer 9

• “go out for Ewings and onion rings”
• malignancy of neuroectoderm cells
• diaphysis
• ‘Onion skin’ on xray. Formed by sarcoma pushing out against bone; extra layers of bone are created.

Question 10

Chondroma vs Chondrosarcoma

-how to differentiate

Answer 10

location:
chondroma–hands/feet small bones
chrondrosarcoma–pelvis or central skeleton

Question 11

which bone tumors occur where?

1. epiphysis
2. metaphysis
3. diaphysis

Answer 11

1. epiphysis–giant cell tumor (only)
2. metaphysis–osteochondroma, osteosarcoma
3. diaphysis–Ewing’s sarcoma, chondrosarcoma

Question 12

Which tumors are associated:

1. childhood, adolescence
2. young adults
3. elderly

Answer 12

1. osteosarcoma, ewing’s sarcoma
2. giant cell tumor
3. chondrosarcoma

osteochondroma appears in children and young adults

Question 13

most common bone sarcoma?

what are the others?

Answer 13

• Osteosarcoma

- Ewing’s, chondrosarcoma

Question 14

osteosarcoma common spreads to where?

Answer 14

lung via blood

Question 15

osteosarcoma:

-what genetics increase risk?

Answer 15

1. mutated Rb

2. Li-Fraumeni (mutated p53)

Question 16

osteochondroma:

-what increases chances of transformation into chondrosarcoma?

Answer 16

• normally <1% becomes chondrosarcoma, but 40% if you have Hereditary Multiple Exostoses (HME)
• auto dom. mutation in EXT gene.

Question 17

enchondroma vs periosteal chondroma

Answer 17

enchondroma : chondroma of intramedullary bone

periosteal: cortical surface under periosteum

Question 18

Multiple chondromatosis

Answer 18

• presence of multiple chondromas, appears in:
  1. Ollier’s disease
  2. Maffucci’s syndrome (also has hemangiomas)
• both caused by point mutations

Question 19

Ollier’s disease

Answer 19

• hereditary disease

- presents with multiple enchondromas

Question 20

Maffucci’s syndrome

Answer 20

• hereditary disease

- presents with multiple enchondromas and hemangiomas

Question 21

non-ossifying fibroma

Answer 21

• benign bone lesion
• very common developmental cortical defect (1 in 4)
• usually heals itself

Question 22

Fibrous dysplasia

• appearance on xray
• appearance histology
• associated disorder

Answer 22

-normal bone replaced with fibrous bone tissue

• thinned cortex
• “frosted glass” appearance of bone
• “chinese characters” of randomly oriented bone trabeculae

-McCune-Albright syndrome

Question 23

-McCune-Albright syndrome

Answer 23

presents with:

1. polyostotic fibrous dysplasia (multiple bones)
2. cafe au lait spots
3. endocrine problems

Question 24

Ewing’s sarcoma:

etiology

Answer 24

11: 22 translocation

think: patrick ewing’s jersey was 33, = 11+22

Question 25

80% of secondary bone tumors were metastasized from which 5 organs?

Answer 25

BLT-KP

breast, lung, thyroid, kidney, prostate

Question 26

Unicameral bone cyst (UBC)

Answer 26

-benign bone cyst filled with clear liquid, one cavity

Question 27

Aneurysmal bone cyst (ABC)

Answer 27

-‘honeycomb’ of multiple bone cysts, filled with blood

Question 28

Multiple myeloma

-clinical findings

Answer 28

• involves bone marrow
• lytic lesions throughout skeleton (punched out holes in skull)
• causes pathologic fractures

Question 29

if on xray you see bone matrix formation, suspect what?

Answer 29

-osteosarcoma

Question 30

CD99

Answer 30

use to diagnose Ewing’s sarcoma