Pathoma - MSK - Bone Tumors

Question 1

Is an osteoma benign or malignant and what is the most common location?

Answer 1

Benign tumor of bone

Most commonly arises on teh surface of facial bones

Question 2

What bone tumor is commonly associated with Gardner syndrome

Answer 2

Osteoma

Gardner = familal adenomatous polyposis + fibromatosis in the retroperitoneum + osteoma of the facial bone

Question 3

What is osteoid osteoma a tumor of?

Answer 3

Benign tumor of osteoblasts (that produce osteoid) surrounded by a rim of reactive bone

Question 4

Where is the common location of an osteoid osteoma?

Answer 4

Cortex of long bones - usually within the diaphysis

Question 5

What is the age group usually affected by osteoid osteomas?

Answer 5

Young adults < 25 y/o (more common in males)

Question 6

Describe imaging and presentation of osteoid osteoma

Answer 6

Presents as bone pain that resolves with aspirin

Imaging reveals a bony mass (< 2 cm) with a radiolucent core (osteoid)

Question 7

Differentiate between an osteoid osteoma and an osteoblastoma

Answer 7

Osteoid osteoma:

• Smaller (< 2 cm); within cortex of diaphysis; bone pain responds to aspirin

Osteoblastoma:

• Larger (> 2 cm); within the vertebrae; bone pain does not respond to aspirin

Question 8

What is an osteochondroma

Answer 8

Tumor of bone with an overlying cartilage cap

Question 9

Where does an osteochondroma arise from

Answer 9

Arises from a lateral projection of the growth plate (metaphysis); bone is continuous with bmarrow space

Question 10

What is a complication of osteochondroma

Answer 10

Overlying cartilage can transform (rarely) into chondrosarcoma

Question 11

What is an osteosarcoma?

Answer 11

Malignant proliferation of osteoblasts

Question 12

What is the age group usually affected by osteosaroma?

Answer 12

Peak incidence in in teenages; smaller and less common peak seen in the elderly

Bimodal distribution

Question 13

What are predisposing factors for osteosarcoma

Answer 13

Familial retinoblastoma, Paget disease, radiation, Li-Fraumeni syndroms (p53 mutation)

Question 14

What part of the bone does osteosarcoma commonly occur in?

Answer 14

Metaphysis of long bones (growth plate)

Usually the distal femur or proximal tibia (regin of the knee)

Question 15

Describe imaging of osteosarcoma

Answer 15

A destructive mass with a sunburst appearance and lifting of the periosteum (Codman triangle)

Question 16

What is the composition of a giant cell tumor

Answer 16

Tumor comprised of multinucleated giant cells and stromal cells

Locally aggressive benign tumor

Question 17

What location do giant cell tumors commonly occur

Answer 17

Arise in the epiphysis of long bones (only tumor that arises in the epiphysis)

Usually in the distal femur or proximal tibia (region of the knee)

Question 18

Describe the X-ray appearance of giant cell tumor

Answer 18

“Soap bubble” appearance due to reactive bone forming arund the tumor in the epiphysis

Question 19

What is Ewing Sarcoma

Answer 19

Malignant proliferation of poorly differentiated cells derived from neuroectoderm

Question 20

Describe location and population affected by Ewing sarcoma

Answer 20

Arises in the diaphysis of long bones

Usually in male children (< 15 y/o)

Question 21

Describe biopsy of Ewing sarcoma

Answer 21

small, round blue cells that resembly lymphocytes

Question 22

Describe X-ray of Ewing sarcoma

Answer 22

“Onion-skin” appearance - tumow will growth within meduallary center of bone and push outwards, causing the periosteum (outer layer) to lay down new layers of bone

Question 23

What is the tranlocation characterstic of Ewing Sarcoma

Answer 23

t(11;22)

Question 24

Differentiate chondroma from chondrosarcoma

Answer 24

Chondroma:

• Benign tumor of cartilage; arises in small bones of hands and feet

Chondrosarcoma:

• Malignant tumor of cartilage; arises in medulla of pelvis or central skeleton

Question 25

Descibe most common location (epiphysis, metaphysis, or diaphysis) of bone tumors (Osteoid osteoma, osteosarcoma, osteochondroma, giant cell tumor, Ewing sarcoma)

Answer 25

Epiphysis - Giant cell tumor

Metaphysis - Osteochondroma, Osteosarcoma

Diaphysis - Osteoid osteoma, Ewing Sarcoma,