Osteochondroma (dr. mahesh)
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Transcript of Osteochondroma (dr. mahesh)
OSTEOCHONDROMA
DR. MAHESH CHAUDHARYPHASE-A RESIDENT
RADIOLOGY & IMAGINGBSMMU
DEFINITION
• Other names:
Cartilage caped exostosis
Osteo-cartilaginous exostosis
• 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 parent bone
GENERAL CONSIDERATIONS
• 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 (diaphyseal aclasia)
• Usually occurs in bones preformed in cartilage
INCIDENCE
• Most common skeletal growth tumor
• Approximate incidence is 50% of all benign bone tumors
• Male : Female ratio 1:1 (?2:1)
• Most are encountered in childhood and adolescence
• Usually follows minor trauma
• Many cases may not be diagnosed due to the silent nature of the disease
PATHOPHYSIOLOGY• Osteochondromas are 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.
• Osteochondromas enlarge from growth at the cartilage cap
• After adolescence and skeletal maturity, osteochondromas usually exhibit no further growth.
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 & normal bone marrow particle.
LOCATION(common)
BONE PERCENTAGE
Femur 34
Humerus 18
Tibia 15
Pelvis 8
Scapula 5
Ribs 3
UNCOMMON SITES (17%)
• Metacarpals
• Condylar process of the mandible
• Base of the skull
• Talus
• Calcaneus
• Spine
• Distal end of the clavicle
TYPICAL INVOLVEMENT • Spine lesions are typically located at the secondary
ossification centres
• Scapular involvement is seen at 1. Inferior angle 2. Superior angle 3. Coracoid process
• Pelvic involvement is most commonly near the 1. Anterior superior iliac spine 2. Ischiopubic synchondrosis
• Large enough lesions are termed as cauliflower exostosis
• Anterior aspects of the ribs are most commonly involved
TYPES
TYPE SESSILE PEDUNCULATED
Incidence Uncommon Common
Location Proximal humerus and scapula
Knee , hip and ankle
Appearance
Flat plateau like stalk producing a broad based protuberance
• Elongated bony stalk merging with the host bone
• The hyaline cap is lobulated giving its appearance
SESSILE VARIANT
Solitary Osteochondroma Lateral radiograph of a sessile osteochondroma of the distal femur.
PEDUNCULATED VARIANT
Solitary osteochondroma Lateral radiograph of a pedunculated osteochondroma of the distal femur.
CLINICAL FEATURES
• Most are asymptomatic
• Symptoms arise as a result of their 1. Location: Tendon or nerve irritation2. Size3. Pressure effects on adjacent structures
• Usual complaint is hard palpable mass
COMPLICATIONS COMPLICATION PERCENTAGE
Fracture 7
Deformity 23
Vascular injury 7
Neurological compromise 10
Adventitious bursae formation 27
Mechanical irritation 10
Malignancy ( Solitary / HME ) <1 , > 10
RADIOLOGICAL INVESTIGATIONS
X - RAY
PENDUNCULATED VARIANT• Knee is the most common location
• Metaphysis is the common site of involvement
• Lesion has a slender stalk with a cartilaginous dome
• The cartilage may show dense amorphous / spotty calcification
• COAT HANGER EXOSTOSIS : The lesion invariably point away from the joint due to muscle pull
X - RAY
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
ULTRASONOGRAPHY• Ultrasonography can be applied to analyze
the cartilaginous cap of an osteochondroma.
• The cap appears as a hypoechoic layer covering a hyperechoic underlying bone.
• 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.
X-ray AP of left thigh
USG of the left thigh above the lump
MRI• MR imaging is the best radiologic imaging method
evaluating hyaline cartilage cap.
• The high water content in non mineralized areas of the cartilage cap has intermediate to low signal intensity on T1-weighted images and high signal intensity on T2-weighted images.
• Mineralized areas in the cartilage cap had low signal intensity on T1 and T2-weighted images
• In young patients with active growth and maturation from normal enchondral ossification in the cartilage cap may be marked heterogeneity both T1-weighted images and T2-weighted images because of the mixture of non mineralized and mineralize cartilage tissues.
Selected T1 and T2 weighted images shown above demonstrate a broad based exophytic lesion of bone. The marrow space of the bone and the lesion are contiguous. There are areas of T2 brightening at the periphery of the lesion, but without frank invasion of the surrounding tissues.
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
• However, it can be very difficult to correctly measure the thickness of a totally nonmineralized cartilage cap because it cannot be easily differentiated from surrounding muscle or bursa.
• Cartilage cap thickness greater than 1 to 2 cm in adults and 2 to 3 cm in growing children suggests malignant transformation
CT through the proximal tibia showing a tibial osteochondroma (arrow) causing marked thinning of the adjacent fibula (arrowhead).
Multiple osteochondromatosis. Nonenhanced, axial computed tomography (CT) scan through the pelvis. Note the fragmentation of the osteochondroma and the considerable soft-tissue mass.
MALIGNANT TRANSFORMATION
CLINICAL
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
MALIGNANT TRANSFORMATION
RADIOLOGICAL
1. Visualized cartilage cap measures >2 cm in adults and >3 cm in children
2. Bone destruction
3. Dispersed calcification in cartilaginous cap
4. Soft tissue mass
5. Altered appearance on sequential studies
6. Increase uptake in bone scan (Unrelaible)
Associations and Syndromes
Hereditary multiple exostoses (diaphyseal aclasis)
• Autosomal dominant condition
• Short stature
• Multiple osteochondromas
• Asymmetric growth at the knees and ankles
• Risk of malignant degeneration is about 10% & often around the hip
Dysplasia epiphysealis hemimelica (DEH, Trevor’s disease)
• Osteochondromas arising in the epiphyses
• Involve the joint
• Lesions restricted to one side of the body–either left or right
• May be multiple lesions in a single limb
• Primarily involves one side of an epiphysis
• Medial side is affected twice as often as the lateral side
• Usually occurs in infants or young children
Enchondromatosis (ollier disease)
Nonhereditary abnormality in which multiple enchondromas
are present. Many lesions become stable at puberty. Risk of malignant transformation to chondrosarcoma is 25%.
Radiographic Features
• Multiple radiolucent expansile masses in hand and feet
• Hand and foot deformities
• Tendency for unilaterality
Imaging Differential diagnosis
Hands- Bizarre parosteal osteochondromatous proliferation (BPOP)
• Does not have cartilaginous cap.
• Seen in hands and feet.
• Continuity between the lesion
and underlying bone is not found
• Bony growth projecting into soft tissues .
Humerus - Supracondylar spur :
• Anatomical variant present in ~1% of the population
• Usually asymptomatic
• Considered if patients present with
symptoms of median nerve compression
and there is no pathology on imaging of
the carpal tunnel.
a bony spur projecting antero-
medially from humeral metadiaphysis
(towards elbow joint)
Osteochondromatous Variants
Dysplasia epiphysealis hemimelica
Subungual exostosis
Turret exostosis
Traction exostosis (at tendinous attachments)
Bizarre parosteal osteochondromatous proliferation = Nora lesion
Florid reactive periostitis
TreatmentNo treatment necessary for asymptomatic osteochondromas (Observation)
If the lesion is causing pain or neurologic symptoms due to compression, it should be resected at the base
None of the cartilage cap or perichondrium should be left in the resection bed or recurrence can occur.
As long as the entire cartilage cap is removed there should be no recurrence
Patients with many large osteochondromas should have regular radiographic screening exams for the early detection of malignant transformation
REFRENCES • BOOKS:
1. Text book of Radiology & Imaging: David Sutton
2. Essentials of Skeletal Radiology: Yochum and Rowe
3. Bone and Joint Imaging : Resnick
• WEB:1. http://radiopaedia.org/articles/osteochondro
ma
2. http://www.learningradiology.com/archives2007/COW%20243-Osteochondroma/osteochondromacorrect.html
THANK YOU…
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