OrthoFracs Logo

Chondrosarcoma

Definition

  • Malignant tumour of cartilage-producing cells
    • Bone, if present, is benign & reactive
  • 20% of primary bone tumours
  • 2nd in frequency to Osteosarcoma
  • Relatively non-aggressive
  • Usually Grade I

Classification

  • Classified according to
    • Histological grade & subtypes
    • Primary & Secondary
    • Central & Peripheral

(1) Histological Grade & subtypes

  • Based on the histological appearance
    • Conventional chondrosarcoma
      • Hyaline or myxoid cartilage tumour of various grades
    • Special types
      • Clear cell
      • Mesenchymal
      • Soft tissue chondrosarcoma
      • Chondrosarcoma of skull base
      • De-differentiated
  • There is a spectrum of lesions
    • Benign
      • Those that are clearly benign are
        • Osteochondroma (cartilage cap < 2cm)
        • Enchondroma
        • Periosteal chondroma
        • Chondroblastoma
        • Chondromyxoid fibroma
        • Synovial chondromatosis
    • CLUMP
      • Group of tumours that considered borderline or premalignant
      • These lesions called Atypical Enchondroma/ Chondroma or Grade 1/2 Chondrosarcoma
        • Now more commonly called CLUMP lesions
        • Chondroid Lesion of Undetermined Malignant Potential
        • Typically see more cellular appearance & atypical cells
        • May appear as periosteal chondroma or thickening of the the osteocartilaginous cap of osteochondroma

Conventional chondrosarcoma

Grading of Conventional Chondrosarcoma
Grade Descriptions
1 Low Grade
  • Resembles normal cartilage cells with mild cellular atypia
  • Least risk of metastasis
  • Frequent calcification
2 Medium Grade
  • Frequent double nuclei
  • Atypia with plump cells
  • Rare multinucleated giant cells
  • Calcification
3 High Grade
  • Most abnormal-appearing cartilage with highest risk of metastasis
  • Marked atypia & mitotic figures
    • Double nuclei & crowding of lacunae
    • Frequent multinucleated giant cells
  • No calcification
  • lesions in axial skeleton & proximal appendicular skeleton more likely to be malignant than distal limb lesions (ie. the digits)
  • Most chondrosarcomas are grade 1 or 2
  • Chondrosarcomas are occasionally grade 3
  • The only tumour that has higher risk of metastasizing than Grade 3 is De-differentiated Chondrosarcoma

Clear cell chondrosarcoma

  • Young adults 20-50 years
  • M:F – 2:1
  • Low grade usually
  • Thought to be malignant counterpart of the benign chondroblastoma
    • Hence “epiphyseal chondrosarcoma”
  • Most common in
    • Proximal humerus
    • Proximal femur
  • Involve the epiphyseal centre & metaphysis
  • Histology
    • Larger & more rounded tumour cells with clear or vacuolated cytoplasm (sheets of clear cells)
    • Abundant intracellular glycogen
    • Chondroid & osseous matrix with numerous osteoclast-like giant cells (may resemble renal cell carcinoma)
    • Foci of calcification

Mesenchymal chondrosarcoma

  • 2nd-3rd decade of life
  • High-grade
  • Less common than clear cell
  • Most common in
    • Rib
    • Spine
    • Pelvis
    • Femur
  • Can appear in soft tissues
  • Histology
    • Nodules of benign cartilage in background of undifferentiated small round cells (biphasic appearance)
    • Small cell component has appearance of Haemangiopericytoma or Ewings
  • 60% 5 year survival

Soft tissue chondrosarcoma

    • Rare tumour
    • Little about natural history
    • Treated like other STS

Base of Skull chondrosarcoma

  • Confused with chondroma of clivus
  • Presents with neurological deficits
  • Treated with curettage & irradiation

De-differentiated Chondrosarcoma

  • High-grade
  • Non-chondroid sarcoma
  • 10% of all chondrosarcomas
  • Usually arises from
    • Benign cartilage lesion
    • Low grade chondrosarcoma
  • Consists of areas of malignant spindle cells that cannot be recognised of cartilage origin adjacent to areas of neoplastic chondrocytes surrounded by hyaline ± bizarre giant cells
  • Cartilage matrix has tissue resembling
    • Osteosarcoma
    • Fibrosarcoma
    • MFH
  • Most malignant of chondrosarcoma & highest rate of metastasis

(2) Primary & Secondary Types

  • Primary
    • Arise de novo
    • Not associated with pre-existing lesion
  • Secondary
    • 1. From pre-existing cartilage lesions
        • Osteocartilaginous exostosis
        • Enchondroma
        • Periosteal chondroma
        • Chondroblastoma
        • Chondromyxofibroma
        • Synovial chondromatosis
      • Earlier age of presentation than the primary tumours
    • 2. From other cause
        • Pagets
        • Radiation
      • Later presentation than the primary tumours

(3) Central & Peripheral

  • Central (Medullary)
    • Arise from
      • medullary canal
        • Meta-diaphyseal
          • Metaphysis extending into diaphysis
        • Femur & Humerus most commonly
    • All primary types are central
    • Secondary types usually arise from Enchondroma
  • Peripheral (Juxtacortical)
    • Arise from the surface of bone
      • Pelvic & Shoulder girdle
      • Upper Femur & Humerus
      • Ribs
    • Majority secondary to Exostosis

Risk of malignant transformation

  • Solitary osteochondroma < 1%
  • Diaphyseal aclasia 1% per year
  • Solitary enchondroma < 1%
  • Multiple enchondroma (Ollier’s*, Marfucci’s**) 20-30%
  • Synovial chondromatosis 5%
  • *Patients with Ollier’s disease have 25% incidence of chondrosarcoma in lifetime
  • **Patients with Maffucci syndrome have 100% incidence of chondrosarcoma in lifetime
  • Secondary chondrosarcoma from Exostosis & Enchondromas have better prognosis & rarely metastasize (typically Grade I)
  • Only ones that metastasize are those with high grade or de-differentiated tumour
  • Thus enlarging exostotic cap excised in adult due to
    • Local effects
    • Risk of de-differentiation
  • Not due to risk of metastasis

Clinical features

  • Classically patients in 5th-6th decades
  • 4% < 20yo
  • M:F – 1.5:1
  • Long history of pain & mass
  • Most commonly seen in medullary cavity of
    • Femur
    • Humerus
    • Pelvis (incl. acetabulum)
    • Ribs
  • Patients initially complain of mild local pain & swelling
  • Laboratory findings normal

Radiography

Central

  • Diaphyseal or less often Metaphyseal
  • Lucent expansile lesion
  • Sclerotic margins
  • Endosteal scalloping
  • Intralesional calcification
    • Amorphous
    • Punctate
    • Chicken Wire
    • Popcorn
  • Cortical destruction & soft tissue mass may be present
  • More destructive lesions have
    • Less calcification
    • More scalloping
    • More cortical destruction

Peripheral

  • Soft tissue mass
  • Multiple calcific densities
  • Ill-defined margins
  • Destruction of underlying bone
  • Some are using Thallium & DMSA scans to differentiate low from high grade lesions
    • uptake suggests ↑ metabolic activity (ie. high grade lesion)
  • Approach to CLUMP lesions
    • Bone scan cold
      • expect good histological characteristics
      • no need to biopsy
    • Bone scan hot
      • may have worrying histological features
      • MRI with gadolinium producing a contrast enhancement curve with images taken at a specific site every 7 seconds for 2 minutes
      • if there is a steep curve (rapid take-off) then suggestive of angiogenesis which may indicate aggressive lesion
      • if so then should consider biopsy

Histology

Gross

  • Pearly white
  • Cauliflower-like mass
  • Surrounded by pseudocapsule

Histology

  • Lobules of cartilage
  • Matrix may have
    • Calcification
    • Necrosis
    • Myxoid degeneration
  • Features that suggest malignancy
    • Pleomorphism
    • Hypercellularity
    • Mitotic figures
    • Double nuclei in single lacunae
    • Multinucleated Giant Cells
  • Realise that the pathologist will accept chondromas with atypical features (↑ cellularity, binucleate cells, anaplasia etc) for certain lesions & still call them benign
    • Solitary enchondroma
    • Olliers or Marfucci’s
    • Periosteal chondroma
    • Synovial chondromatosis
  • Some chondromas are indistinguishable from low grade chondrosarcoma
  • 50% of Grade I chondrosarcomas are indistinguishable from cellular enchondroma
    • Distinction is made on the radiological appearance (bone destruction etc), soft tissue extension, location etc
    • Enchondromas & periosteal chondromas should be reviewed every year to see if they progress or change (particularly if multiple or part of a syndrome)

Grading

  • Grading based on complete patient
    • Age
    • Location
    • XR
    • Histology (see above)
  • More likely to be worrisome if
    • Central
    • Large
    • Old patient
    • Polyploid

Differential Diagnosis

  • Other cartilage tumours
    • Enchondroma
    • Osteochondroma
    • Chondroblastoma
    • Chondromyxoid fibroma
  • Chondrosarcomatous osteosarcoma

Treatment

  • The mainstay of treatment is wide surgical resection
  • Highly resistant to chemotherapy & DXRT
    • Rate of DNA synthesis slow
    • Slow growing, low grade nature of tumours
  • Surgery should aim to be curative but sometimes margins are close d/t location of neurovascular structures
  • Aggressive excision with wide margin
    • Probably safest regardless of grade
  • Adjunctive treatment rarely used
  • May be indicated in
    • High grade lesions
    • Incomplete margins
      • Phenol to lyse remaining tumour cells then neutralised with alcohol
  • Irradiation most useful where wide resection not possible (eg. spine)
    • High dose irradiation can arrest growth of the tumour for several years but will only delay the local recurrence
  • Chemotherapy has been limited to the young patient with de-differentiated chondrosarcoma
    • Little data to support usage & in metastatic disease will slow growth but cure rare

Prognosis

  • Low-Moderate Grade
    • If treated with wide excision
    • 90% 5-year survival
  • High Grade
    • < 10% 5-year survival
  • Thus patients with low grade tumours can expect a cure but metastasis common in high grade
  • Depends on
    • Histological grade
    • Adequacy of resection
Bookmark and Share