Chrondrogenic tumours

Question 1

what is an enchondroma?

Answer 1

• A Benign chrondrogenic tumour- 2nd most common
• composed of Hyaline cartilage
• caused by abnormality in chondrocyte function in the physis
• M=F
• most common 20-50 yrs
• usually in medullary canal in diaphysis and metaphysis
• most common in hand 60%
• location
  
  • ​distal femur, proximal humerus,tibia
  • rare in spine/pelvis

Question 2

What is the pathophysioogy of enchondroma?

Answer 2

• enchondromas represent incomplete endochondral ossification
• chondroblasts and fragments of epiphyseal cartilage escape from the physis, displace into the metaphysis and proliferate there

Question 3

Name associated conditions of enchondromas?

Answer 3

• Solitary enchondromas
• Ollier’s disease
  
  • multiple enchondromatis
  • no genetic predisposition
  • skeletal dysplasia with failure of normal endochondral ossification
  • enchondromas throughout the metaphyses and diaphyses of long bones
  • involved bones are dysplastic, with shortening and bowing
  • risk of malignant transformation <30%
• ​Maffucci syndrome
  
  • ​sporadic inheritance
  • multiple enchondromas & soft tissue angiomas
  • risk of malignancy 100%
  • increased risk of visceral malignancy

​

Question 4

Can you describe the enneking staging of benign lesions?

Answer 4

• Grade 1- Latent lesion-= enchondroma, non ossfiying fibroma
• Grade 2- Active lesion =ABC/UBC/Chondroblastoma
• Grade 3- Aggressive lesion = GCT

Question 5

Describe the symptoms and signs of enchondromas?

Answer 5

Symptoms

• asymptomatic- found incidentially- tibia
• pathologcial fx- hand
• Pain - uncommon
  
  • most chondrosarcomas have non mechanical pain

Signs

• Angular deformity and shortening
• blusih angiomas of maffucci

Question 6

What is seen on xrays of enchondromas?

Answer 6

• pop corn stippled calcification & rings
• bone expansion
• Lytic in hand
• in Maffucci = angiomas are visible as calcified phleboliths

Question 7

How are chondrosarcomas different from enchondromas?

Answer 7

• unlike enchondromas, chondrosarcomas display
  
  • cortical thickening and destruction
  • endosteal erosions and scalloping >50% of the width of the cortex

are larger (>5cm)

Question 8

Describe the histology in enchondromas?

Answer 8

• hypocellular with bland, mature hyaline cartilage (blue balls of cartilage) separated by normal marrow

Question 9

Describe the tx of enchondromas?

Answer 9

• non operative
  
  • observation
    
    • majority
    • with serial xrays in 3-6months for 1-2 years
    • long term FU with multiple enchondromas
• Surgery
  
  • intralesional curettage & bone graft
    
    • lesions that show any change in lesion
  • immobilisation, currettage & bone graft
    
    • path fx
    • immobilisatio until union then currettage & BG

Question 10

What is periosteal chondroma?

Answer 10

• A rare type of chondroma - benign
• occurs on surface of long bones
  
  • under periosteum of distal femur,prox humerus and prox femur
  • 59% prox humerus
• 10-20 yrs old

Question 11

what are the symtpoms of periosteal enchondromas?

Answer 11

• Pain
  
  • 2ary to irriation from tendons

Question 12

What is seen on radiographs with periosteal enchondromas?

Answer 12

• saucerization of underlying bone
• punctate mineralisation in 1/3
• well demarcated, shallow cortical defects

Question 13

What is seen on histology of periosteal enchondromas?

Answer 13

• Bland hyaline cartilage
• small chondroid cells in lacunar spaces

Question 14

What is the tx of periosteal enchondromas?

Answer 14

• Operative
  
  • marginal excision including underlying cortex
  • if symptoms intereferring with function
  • lesion with reoccurif cartilage is left behind

Question 15

What is an osteochondroma & multiple hereditary exostosis?

Answer 15

• A Benign chrondrogenic lesion derived from aberrant cartilage from the periochondral ring that may take the form of
  
  • solitary osteochondroma
  • Multiple hereditary exostosis ( MHE)
• ​Most common Benign bone tumour
• Many asymptomatic
• common adolescents/young adults
• location on surface of bones, often at sites of tendon insertions
  
  • knee
  • prox femur
  • prox humerus
  • sugungal exostosis- at hallux
• Autosomal Dominant
• Mutation in EXT gene affects prehypertrophic chondrocytes of growth plate

Question 16

What are the associated conditions of osteochondroma & multiple hereditary exostosis?

Answer 16

• Secondary Chondrosarcomas
  
  • a malignant condition that results from malignant transformation of solitary osteochondromas or MHE
• occurs older pts - 50 yrs
• most common location is the pelvis

Question 17

What is the prognosis of osteochondroma & multiple hereditary exostosis?

Answer 17

• Risk of malignant change
  
  • <1% solitary osteochondromas
  • 5-10% in multiple hereditary exostosis develop secondary chondrosarcomas

Question 18

Define multiple hereditary extosis

Answer 18

• Disorder characterised by multiple osteochondromas
• mutation affects the prehypertrophic chondrocytes of the physis
• Autosomal Dominant
• mutations in EXT1 ,EXT2, EXT 3 genes = tumour suppressor genes
• ext1 individuals > severe presentation cf EXT 2 mutations
  
  • higher rate of osteosarcomas
  • more exostoses
  • more limb malignment

Question 19

What is the prognosis of MHE?

Answer 19

• 5-10% malignant change to chondrosarcomas
• proximal lesions more likely to undergo malignant transformation than distal lesions

Question 20

What are the symptoms of osteochondromas?

Answer 20

• most asymptomatic
• painless mass
• NV compromise
• mechanical symptoms

Question 21

What are the symptoms of MHE?

Answer 21

Limb deformities

• femoral shortening & LLD
• coxa Valga
• knee valgus- shortened fibular, patella dislocation
• ankle valgus- shortened fibular
• upper limb- ulna shortening, radial head dislocation/radial bowing
• nay increase in acute apain should raise suspicion of malignancy

Question 22

What is seen on radiographs with osteochondromas & multiple hereditary exostosis?

Answer 22

• Sessile ( broad base)
• Pedunculated ( narrow stalk)
• found on surface of bones
  
  • >malignancy risk in sessile lesions
  • pedunculated point away from joint
• cortex of lesion continous w cortex of native bone
• medullary canal of lesion continous w medullary cavity of native bone

Question 23

What is the histology of osteochondroma & multiple hereditary exostosis?

Answer 23

• similar to normal physis with
• cartilage cap consisting of hyaline cartilage
• normal primary trabeculae
• linear clusters of active chondrocytes
• may have thin cartilage cap covering the lesion

Question 24

What is the tx of osteochondroma

Answer 24

• Non operative
  
  • Observation
    
    • asymptomatic
• Surgery
  
  • Marginal resection at base of stalk including cartilage cap
    
    • ​symptomatic lesions
    • delay surgery until skeletal maturity

Question 25

What is the tx of multiple hereditary exostosis?

Answer 25

• non operative
  
  • observation
  • most don’t require intervention prior to reaching skeletal maturity
• Operative
  
  • Surgical excision of osteochondromas
    
    • if dislocation of radial head
    • loss of forearm rotation
    • optimises chances of improved motion

Question 26

tx of secondary chondrosarcomas

Answer 26

• Operative
• wide surgical resection
  
  • tx as typical condrosarcoma

Question 27

what are the complications of osteochondroma & multiple hereditary exostosis?

Answer 27

• Pseudoaneursym of popliteal artery
• nerve compression
  
  • ​sciatic/common peroneal n, radial n
• tendon compression
• Chondrosarcoma
  
  • in adults cartilage cap >2cm assoc with increased risk of malignancy
  • mean age of dx 31yrs
• Bursa formation
• reocurrance
  
  • 2-5% post resection

Question 28

What are the differential dx of a surface lesion?

Answer 28

• Osteochondroma/ MHE
• Periosteal chondroma
• Parosteal osteosarcoma
• Periosteal osteosarcoma

Question 29

Define chondroblastoma?

Answer 29

• A benign chondrogenic lesion
• differs to GCT by chondroid matrix
• 2:1 male/female
• most pts <25yrs
• location= Epiphyseal lesion in young pts
• apophysis/ distal femur/ prox tibia/ prx humerus/prox femur
• Typically epiphyseal but may cross Physis
• chromosome abnormalities 5/8

Question 30

What is the prognosis of chondroblastoma?

Answer 30

• 1-2% benign chondroblastoma metastasise to lungs
• similar to GCT
• reocurrance 10-15% post surgicla resection

Question 31

what are the symptoms of chondroblastoma?

Answer 31

• Increase pain in involved joint

Question 32

what is seen on xrays with chondroblastoma?

Answer 32

• Well circumscribed epiphyseal lytic lesion- thin rim of sclerotic bone that is sharply demarcated from normal medullary cavity
• lesions often cross physis into metaphysis
• cortical expansion present
• soft tissue expansion rare

Question 33

What is the DDX of the radiograph?

Answer 33

• Giant cell tumour
• chondroblastoma
• clear cell chondrosarcoma
• Osteomyelitis

Question 34

What is seen on histology in chondroblastoma?

Answer 34

• Chondroblastoma arranged in Cobblestones or dhicken wire- see pic
• occasional multinucleated giant cells
• scattered multinucleated giant cells with focal areas of chondroid matrix

Question 35

Describe the tx of chondroblastoma?

Answer 35

• operative
  
  • Extended intralesional curretage and bone grafting
    
    • ​in symptomatic pts
  • resection of rare benign pulmonary mets
    
    • ​if pulmonary mets exist

Question 36

Describe chondromyxoid fibroma?

Answer 36

• A rare
• Benign chondrogenic lesion
• characterised by variable amounts of chondroid, fibromatoid and myxoid elements
• > in males
• most common in 2nd/3rd decades of life
• location
  
  • long bones- tibia, distal femur, pelvis ot hands
• Mutations of chromosome 6 position q13
• may reocur in 20-30% cases

Question 37

What are the symptoms of chondromyxoid fibroma?

Answer 37

• Long standing pain- months- years
• Pain and swelling

Question 38

What is seen on xrays with chondromyxoid fibroma?

Answer 38

• Lytic, eccentric metaphyseal lesion
• scalloped and sclerotic rim
• calcifications RARE

Question 39

What is seen on mri with chondromyxoid fibroma?

Answer 39

• T1 weighted low signal
• T2 weighted high signal

Question 40

What is seen with histology with chondromyxoid fibroma?

Answer 40

• Lobules of fibromyxoid tissue
  
  • hyperchromatic nuclei
  • lobules contain spindle shaped cells/stellate shaped
  • high power stellate cells seen

Question 41

What is the tx of chondromyxoid fibroma?

Answer 41

• Operative
• intralesional curretage & bone graft ( or PMMA)
  
  • mainstay of tx

Question 42

what are the complications of chondromyxoid fibroma?

Answer 42

• Reocurrance 25% cases

Question 43

What is Chondrosarcoma?

Answer 43

• A Malignant chondrogenic lesion that can occur in 2 forms
  
  • primary chondrosarcoma
    
    • low grade,high grade
    • clear cell chondrosarcoma
    • mesenchymal chondrosarcoma
  • Secondary chondrosarcoma
    
    • arises from benign cartilage lesions
      
      • osteochondromas
      • Mutliple hereditary exostosis
      • Enchondromas (1% transformation)
      • Ollier’s disease (20-45% transformation)
      • Maffucci ( 100% transformation)

Question 44

Describe the epidemiology of chondrosarcomas?

Answer 44

• Age
  
  • older pts 40-75 yrs
  • slight male predominance
  • locations= pelvis, prox femur, scapula
  • 85% of chondrosarcomas are grade 1/2
  • axial and proximal extremity lesions have a more aggressive course
  • survical
    
    • grade 1 = 90%
    • Grade 3= 30-50%
    • de differentiated 10%

Question 45

Describe clear cell chondrosarcomas?

Answer 45

• malignant immature cartilagenous toumour
• accounts for
• common 30-040 yrs
• insidious onset of pain
• epiphyseal in location ( ddx from GCT ( giant cells) /chondroblastoma ( young pts)
• locally destructive with potential to metastatsize

Question 46

describe mesenchymal chondrosarcomas?

Answer 46

• chondrosarcomas variant which present with a biphasic pattern of neoplastic cartilage with associated neoplastic small round blie cell component
• younger pts
• tx includes neoadjuvant chemo then wide surgical resection

Question 47

What does a pt with chondrosarcomas present with?

Answer 47

• Pain - most common
• slow growing mass/ bladder or bowel obstruction ( mass effect in pelvis)
• 50% of de-differentiated chondrosarcomas pc pathological fracture

Question 48

What is seen on xrays in a pt with chondrosarcomas?

Answer 48

• Lytic or blastic reactive thicknening of cortex
• low grade
  
  • similar appearance to enchondroma w additional cortical thickneing/expansion
• high grade
  
  • cortical destruction & a soft tissue mass
• intra-lesional ‘popcorn mineralisation’
• MRI- useful ti determine cortical destruction
• bone scan- v hot

Question 49

Describe the histology of chondrosarcomas?

Answer 49

• No needle biopsy as difficulties in diagnosis
• low grade
  
  • few mitotic figures with bland histologic appearance
  • enlarged chondrocytes w plump nucleated lacunae - see pic
• high grade
  
  • hypercellular stroma w blue balls of cartilage lesion which permeate the bone traecular
• De differentitated- high level of spindle cells

Question 50

What is the tx of chondrosarcomas?

Answer 50

• Operative
  
  • Intra-lesional curettage
    
    • grade 1 lesions
  • Wide local excision
    
    • ​grade 2/3 lesions
    • no sig role for radiotherapy/chemo as cartilage lesion is slow growing in typically intramedullary chondrosarcomas
  • Wide local excision w multi-agent chemo
    
    • mesenchymal chondrosarcomas
    • the role of chemo in de-differentiated very controversial