Osteochondroma is a benign bone tumor that projects from the external surface of bones. It consists of a cartilage cap and bony projection. Solitary osteochondroma involves one bone, while multiple osteochondromas can involve several bones and are associated with hereditary multiple exostosis. Osteochondromas are most common in children and adolescents, usually causing no symptoms, though sometimes pain or pressure on nearby tissues. While usually benign, osteochondromas have a small risk of malignant transformation. Diagnosis involves x-ray, CT or MRI to identify the connection to the underlying bone and cartilage cap structure. Symptomatic osteochondromas may require surgical excision to relieve symptoms.

1. P R E S E N T E D B Y P E T E R C R O Y
2 0 0 9 B A T C H
M O S C M E D I C A L C O L L E G E
OSTEOCHONDROMA

2. INTRODUCTION
• Osteochondroma is a bony exostosis projecting
from the external surface of a bone.
• It is usually has a hyaline lined cartilaginous cap
• The cortex and spongiosa of the lesion merge with
that of the host bone

3. • When the lesion is seen in a single bone , it is called
solitary osteochondroma
• If two or three bones are involved , with no familial
history , the condition is known as multiple
ostechondromas
• Widespread ostechondromas are associated with a
positive familial history, and the condition is known
as Heriditary Multiple Exostosis

4. INCIDENCE
• Most common skeletal growth/tumor
• Approximate incidence is 50% of all benign bone
tumors
• Male : Female ratio 2:1
• Most are encountered in childhood and
adolescence
• 75% occur before the age of 20
• Many cases may not be diagnosed due to the silent
nature of the disease

5. PATHOPHYSIOLOGY
• Developmental lesions rather than true neoplasms
• These lesions result from the separation of a
fragment of epiphyseal growth plate cartilage,
which subsequently herniates through the periosteal
bone cuff
• The mechanism likely results from the remodeling
during growth of the long bone.
• Persistent growth of this cartilaginous fragment and
its subsequent enchondral ossification (maturation)
result in a subperiosteal osseous excrescence with
a cartilage cap that projects from the bone surface.
• After adolescence and skeletal maturity,
osteochondromas usually exhibit no further growth.

6. The development of an osteochondroma, beginning
with an outgrowth from the epiphyseal cartilage
 Histology:
•Covered by thin layer of periosteum.
•Binucleate chondrocytes in lacunae.
•Contains hyaline cartilage, bony tissue
and normal bone marrow particle.

7. LOCATION
(COMMON)

8. UNCOMMON SITES
• Metacarpals
• Condylar process of the mandible
• Base of the skull
• Talus
• Calcaneus
• Spine
• Distal end of the clavicle( can cause rotator cuff
syndrome)

9. TYPES

10. SESSILE VARIANT
• Creates a broad based exostosis
lacking an elongated projection
• Causes a long asymmetric
elongation of the bone
• Amorphous , spotty calcification is
absent
• Occur at the metaphyseal –
diaphyseal region

11. PEDUNCULATED VARIANT
• Knee is the most common location (tibia and fibula)
• Metaphysis is the common site of involvement
• Lesion has a slender stalk with a cartilaginous dome
• The cartilage may show dense amorphous / spotty
calcification

12. CLINICAL FEATURES
• Most are asymptomatic
• Symptoms arise as a result of their
1. Location
2. Size
3. Pressure effects on adjacent structures
• Tendon or nerve irritation
• Usual complaint is hard palpable mass

13. COMPLICATIONS

14. MALIGNANT TRANSFORMATION
• Presents with
1. Growth of lesion after skeletal maturity
2. Pelvis / shoulder (mostly sessile variety)
3. < 1 % in solitary , > 10% in HME
4. Increasing mass and pain at the site of lesion in
absence of fracture, bursitis or nerve compression
• Radiologically
• Bone destruction
• Dispersed calcification in cartilaginous cap
• Soft tissue mass

15. X RAY - PEDUNCULATED
• Lateral radiograph of a
pedunculated
osteochondroma of the distal
femur.
• COAT HANGER EXOSTOSIS :
The lesion invariably point
away from the joint due to
muscle pull

16. X RAY SESSILE
• Lateral radiograph
of a sessile
osteochondroma of
the distal femur.

17. USG
• Ultrasonography can be applied to analyze the
cartilaginous cap of an osteochondroma.
• Ultrasonography is also valuable in the diagnosis of
bursitis and other complications associated with
osteochondromas, such as arterial or venous
thrombosis, as well as aneurysm and
pseudoaneurysm formation.

18. C T SCAN
• Allows optimal demonstration of the
pathognomonic cortical and medullary continuity
of the lesion and parent bone
• Mineralization in the cartilage cap allows a correct
CT measurement
• Cartilage cap thickness greater than 2 cm in adults
and 3 cm in growing children suggests malignant
transformation

19. MRI
• MRI is useful for assessing the continuity of the
parent bone with the cortical and medullary bone
in an osteochondroma.
• MRI also provides information about inflammation in
reactive bursa formation, impingement syndromes,
and arterial and venous compromise. This study is
the method of choice for evaluating compression of
the spinal cord, nerve roots, and peripheral nerves.

20. TREATMENT
• No treatment necessary for asymptomatic
osteochondromas (Observation)
• If the lesion is causing pain or neurologic symptoms
due to compression, it should be Excised
• None of the cartilage cap or perichondrium should be left in
the resection bed or recurrence can occur.
• Patients with many large osteochondromas should
have regular radiographic screening exams for the
early detection of malignant transformation
• In adults if the osteochondroma has recently
become bigger, then urgent surgery is done due to
fear of malignancy

21. HEREDITARY MULTIPLE EXOSTOSIS
• Autosomal dominant condition
• Mutations in the EXT1 and EXT2 genes cause
hereditary multiple exostoses
• Multiple osteochondromas
• Asymmetric growth at the knees and ankles and
Short stature
• Malignant transformation rates as high as 25%

22. THANK YOU