Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Chondrosarcoma

Basics
Description
  • This primary malignant tumor of bone consists of malignant chondrocytes (cartilage cells) and occurs inside a cartilage matrix.
  • It most commonly affects the proximal femur, pelvic girdle, knee, and spine.
  • It has a wide range of biologic behavior .
    • Low grade (grade 1): <5% risk of metastasis
    • Intermediate grade (grade 2): 20-30% risk of metastasis
    • Dedifferentiated (grades 3 and 4): 70% risk of metastasis
    • Mesenchymal: >50% risk of metastasis
Epidemiology
Incidence
  • Chondrosarcomas comprise 20% of all primary malignant bone tumors, occurring 1/2 as often as osteosarcoma .
  • The tumor usually occurs in individuals in the 6th-8th decades of life.
Risk Factors
  • Multiple exostoses
  • Ollier disease
  • Maffucci syndrome
Genetics
  • Not much is known.
  • Numerous chromosomes have been implicated, including changes on chromosomes 2-11, 14, 15, and 21 .
  • Patients with hereditary multiple exostoses and an EXT1 mutation are at higher risk than are patients with an EXT2 or EXT3 mutation.
  • Myxoid chondrosarcoma is associated with a 9-22 chromosomal translocation .
Etiology
  • Most chondrosarcomas arise de novo(primary chondrosarcomas), whereas some arise in preexisting lesions (secondary chondrosarcomas).
  • Secondary chondrosarcomas may arise in pre-existing lesions, such as in osteochondromas or the enchondromas in patients with Ollier disease and Maffucci syndrome.
  • Dedifferentiated chondrosarcomas occur in 10% of patients and are high-grade lesions.
Associated Conditions
Multiple exostoses or enchondromatosis
 
Diagnosis
Signs and Symptoms
  • The insidious presentation of deep pain often occurs over years to decades.
  • Pain is somewhat relieved by NSAIDs or narcotic pain medication.
  • A soft-tissue mass may be palpable in long-standing disease with soft-tissue extension.
History
  • Physicians should have a high level of suspicion when:
    • Pain occurs at night.
    • Pain is unrelieved by rest.
Physical Exam
  • Physical examination is not specific.
  • Patients may have pain with deep palpation or a palpable soft-tissue mass.
Tests
Lab
Serum tests generally do not help establish the diagnosis.
 
Imaging
  • Radiography:
    • Plain AP and lateral radiographs usually are diagnostic.
      • Chondrosarcoma usually is described as an intramedullary lesion with stippled and ring-like calcification.
      • Cortical bone changes usually are substantial: erosions, thickening, and bone destruction.
  • Chest radiographs and CT scans usually are obtained in this age group because of the possibility of metastatic disease.
  • MRI of the affected region is helpful for delineating soft-tissue extension and planning the biopsy site and the margins of resection.
Pathological Findings
  • Histologically, it is difficult to differentiate between well-differentiated chondrosarcomas and chondromas (benign).
  • The radiographic features are correlated with the histologic features to establish the degree of malignancy.
  • Chondrosarcoma features include:
    • Permeation of the trabecular bone
    • Chondroblasts in a chondroid matrix
    • Lobular pattern of growth
    • Binucleate chondroblasts
    • Grades 1-3, based on the level of anaplasia
Differential Diagnosis
  • Enchondroma
  • Bone infarct
Treatment
General Measures
  • Surgery is the mainstay of treatment.
  • Chemotherapy and irradiation usually are not used.
  • The goal of treatment is to minimize the chance of recurrence by resection of the entire lesion.
  • For grade 1 tumors, resection and serial 6-month observation with plain radiographs are all that is necessary.
  • Patients with grade 2 and 3 chondrosarcomas are followed with CT scans of the chest at 6-month intervals.
  • At the 5-year disease-free interval, the frequency of clinic visits and repeated radiographs may be safely decreased.
Special Therapy
Physical Therapy
Physical therapy is used for gait training and to regain ROM and strength.
 
Medication (Drugs)
Patients who develop metastases are treated with chemotherapy, but unfortunately, no consistent benefit has been shown with this modality  .
 
Surgery
  • Wide resection involves removal of all diseased bone, with a cuff of normal tissue.
  • The limb can be reconstructed using an allograft or a custom prosthesis.
  • Muscle flaps are used as necessary to fill in soft-tissue defects.
Follow-up
Prognosis
  • Depends on the grade of the lesion:
    • Grade 1: Excellent (<5% incidence of metastasis)
    • Grade 2: Very good (<30% incidence of metastasis)
    • Grades 3 and 4:
      • Poor, >70% incidence of metastasis
      • In 1 study, the overall 5-year survival rate was 7.1%, and the median survival time was 7.5 months .
  • Likewise, mesenchymal chondrosarcomas carry a poor prognosis.
Complications
  • Local recurrence
  • Metastases in medium- and high-grade tumors
  • Failure of reconstruction
Patient Monitoring
Patients are followed at 1-3-month intervals until rehabilitation is complete.

Miscellaneous
Codes
ICD9-CM
170.9 Primary bone neoplasm (malignant)
 
Patient Teaching
The patient should be told that this neoplasm requires correlation of histologic features with radiography for proper diagnosis and that surgery is the mainstay of treatment.
 
FAQ
Q: What is the most common symptom of chondrosarcoma?
A: Patients describe dull, achy pain that occurs at rest and at night.
 
Q: How are chondrosarcomas treated?
A: Patients with chondrosarcoma are treated with wide surgical resection. Radiation therapy or chemotherapy plays no role in treatment.
 
Q: What is the prognosis for patients with chondrosarcoma?
A: Patients with low-grade chondrosarcoma have an excellent prognosis, whereas patients with medium- and high-grade chondrosarcomas have a substantial risk of metastasis (20-30% and >50% respectively).

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