Bone Neoplasms and Benign Tumors

Question 1

What is the most common primary malignant bone tumor in all children?

Answer 1

Osteosarcoma

Question 2

What is the most common primary malignant bone tumor in children <10 years of age?

Answer 2

Ewing sarcoma

Question 3

Know Table 25-3 ***

Question 4

What are the classic (but nondiagnostic) x-ray findings in osteosarcoma vs Ewing sarcoma?

Answer 4

Osteosarcoma can have the lytic “sunburst” pattern (less commonly), while Ewing has the lytic “onion skinning” pattern.

Question 5

In what age group are most osteosarcomas seen?

Answer 5

Osteosarcoma occurs most commonly during the adolescent growth spurt.

Question 6

In people with what (4) conditions does osteosarcoma occur at a higher rate?

Answer 6

Hereditary retinoblastoma, Li-Fraumeni syndrome, Rothmund-Thomson syndrome (short stature, skin telangiectasias, small hands/feet, hypoplastic or absent thumbs), and people who have a history of radiation therapy for Ewing sarcoma or other malignancies.

Question 7

What are (3) benign conditions with potential for malignant transformation to osteosarcoma?

Answer 7

Paget disease, endochondromatosis, and multiple hereditary exostoses.

Question 8

In what part of the bone does osteosarcoma most commonly occur?

Answer 8

Osteosarcoma most commonly occurs in the metaphyseal region of the long bones and invades the medullary cavity.

Question 9

How does osteosarcoma usually present?

Answer 9

Unilateral pain and swelling are the most common presenting findings. The most commonly affected joint is the knee, followed by the shoulder.

Question 10

What are clinical clues for osteosarcoma?

Answer 10

Deep bone pain, nighttime awakening, palpable mass, x-ray showing a periosteal reaction (sunburst pattern is classic but is neither common nor specific), Codman triangle can also be seen on x-ray (a reaction seen at the junction of the mass and the periosteum caused by ossification of only the edge of the raised periosteum).

Question 11

How is osteosarcoma typically treated and what is the prognosis?

Answer 11

It is treated with surgical resection (and limb sparing if possible) as well as chemotherapy. 5 year survival rate is 65-75% in patients with nonmetastatic disease. Patients with distant bone metastases and widespread lung metastases have a poor prognosis.

Question 12

Which chemotherapeutic agents are typically used in the treatment of osteosarcoma?

Answer 12

Doxorubacin, cisplatin, and methotrexate.

Question 13

What is Ewing sarcoma?

Answer 13

Ewing is an undifferentiated sarcoma of bone but can also arise from soft tissue.

Question 14

What chromosomal abnormality is most commonly associated with Ewing sarcoma?

Answer 14

A majority of patients have a t(11;22) translocation, wherease the rest have a t(21;22).

Question 15

How does Ewing sarcoma typically present? What usually differentiates its presentation from that of osteosarcoma?

Answer 15

Patients typically present with pain and swelling, similarly to osteosarcoma. However, patients with Ewing are more likely to have systemic findings such as fever and weight loss. Flat bones and the diaphyses of long bones are most commonly affected.

Question 16

What is the typical radiologic finding in patients with Ewing sarcoma?

Answer 16

An x-ray showing a primary lytic lesion with a lamellated or “onion skin” periosteal reaction.

Question 17

What is the typical treatment for Ewing sarcoma?

Answer 17

Chemotherapy is usually given first, with local control being achieved by either complete total resection or radiation therapy.

Question 18

What is the prognosis for children with Ewing sarcoma?

Answer 18

In those with small, nonmetastatic, distally-located extremity tumors, prognosis is excellent (>75% cure rate). Those with bulky pelvic tumors, metastatic disease at diagnosis, and bone marrow involvement have a poorer prognosis.

Question 19

What is an osteochondroma?

Answer 19

Osteochondroma is a very common benign bone tumor in children. Most are discovered between 5 and 15 years of age as a bony, nonpainful mass.

Question 20

How does osteochondroma appear on x-ray?

Answer 20

They appear as stalks or broad-based projections from the surface of the bone. Usually there is a cartillage “cap” which can be as thick as 1 cm.

Question 21

Where do osteochondromas typically occur?

Answer 21

Most occur in the metaphysis of long bones, particularly the distal femur, proximal humerus, and proximal tibia.

Question 22

What is endochondroma?

Answer 22

It is a benign solitary lesion of hyaline cartilage that occurs centrally in the bone. The hands are typically affected. Most patients require only observation.

Question 23

What is Ollier disease?

Answer 23

It is a disorder with multiple endochondromas in various locations and results in short stature, limb length inequality, and joint deformity. Malignant transformation is common.

Question 24

What is Maffucci syndrome?

Answer 24

It manifests as multiple endochondromas with angiomas of the soft tissue. Malignant transformation is common.

Question 25

What is a chondroblastoma?

Answer 25

It is a rare, benign, cartilage-forming lesion of the epiphysis of long bones. They can be cured if treated with curettage and bone grafting before joint destruction occurs.

Question 26

Which two bony lesions are commonly used as distractors on board exam questions?

Answer 26

Enochondromas and chondroblastomas

Question 27

What is an osteoid osteoma?

Answer 27

A benign tumor that usually occurs in males between 5 and 20 years of age.

Question 28

How does osteoid osteoma present?

Answer 28

Clinically, there is a characteristic unremitting and worsening pain (worse at night) that, in contrast to osteosarcoma, is relieved with aspirin or other NSAIDs. Palpation and ROM do not worsen the pain.

Question 29

Where does osteoid osteoma usually present?

Answer 29

Proximal femur and tibia.

Question 30

What does x-ray show in patients with osteoid osteoma?

Answer 30

X-rays show a round or oval metaphyseal or diaphyseal lucency surrounded by sclerotic bone.

Question 31

What is osteoblastoma?

Answer 31

A benign bone-forming tumor that causes local destruction of bone and grows over time. It most commonly affects the vertebrae.