Dr. Kevin Yip

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

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Chondroblastoma

Basics
Description
  • A benign tumor of cartilaginous origin with a predilection for the epiphysis in skeletally immature patients
  • Generally found in the epiphyses of long bones.
    • The humerus is most commonly affected, followed by the tibia and femur  .
  • Synonyms: Codman tumor; Epiphyseal chondromatous giant cell tumor
Epidemiology
A slight male predominance (2:1) is noted .

Incidence
  • This tumor is rare.
  • In the largest series, chondroblastoma accounted for 1% of all skeletal neoplasms.
Risk Factors
None known
 
Genetics
No known genetic component exists.
 
Etiology
  • The pathogenesis is unknown.
  • Most authors agree that the neoplastic cells arise from cartilage-forming matrix cells or chondroblasts.
  • The tumor may be related to chondromyxoid fibroma.
Associated Conditions
Aneurysmal bone cyst

Diagnosis
Signs and Symptoms
  • Patients usually complain of mild to moderate chronic pain, often months to years in duration.
  • Stiffness and effusion of the adjacent joint also are common.
  • Local swelling is uncommon.
Physical Exam
  • The adjacent joint may have an effusion and decreased ROM.
  • A soft-tissue mass is uncommon.
  • Joint tenderness is unusual.
Tests
Lab
  • Tests are not helpful.
  • All blood tests are within normal limits, including the ESR.
Imaging
  • Radiography:
    • The radiographic appearance is that of a lytic lesion in the epiphysis with a thin sclerotic rim.
      • The sclerotic rim indicates the benign nature of the lesion.
      • It may expand or deform the bone.
      • Occasionally, punctate calcifications may be seen.
    • The patient’s history and plain radiographs usually are sufficient for making the diagnosis.
  • MRI:
    • May be used if history and radiography are not definitive
    • The boundary of the lesion on MRI scans should be distinct.
Pathological Findings
  • The diagnosis requires the presence of chondroblasts on microscopic section.
    • Chondroblasts are small, round or polygonal cells with round or oval nuclei.
    • Cells are described as looking plump or like fried eggs.
    • A lattice of calcification extends between the cells (chicken wire) .
  • Interspersed giant cells are a common feature and may lead to confusion with giant cell tumor.
  • Areas of aneurysmal bone cyst degeneration also may be present.
Differential Diagnosis
  • Enchondroma
  • Giant cell tumor
  • Osteomyelitis
  • Fibrous dysplasia
Treatment
General Measures
  • Surgical excision is recommended to prevent progressive growth of the lesion with destruction of the epiphysis.
  • Bone grafting is needed.
  • Surgery is sometimes technically demanding because of the need to preserve or reconstruct the nearby joint surface.
Activity
No restrictions on activity are necessary because pathologic fracture is not a problem.
 
Special Therapy
Physical Therapy
Therapy may be used to regain ROM and strength after surgery.
Surgery
  • Because the tumor is considered benign, local measures suffice.
  • Surgery generally involves curettage and bone grafting.
Follow-up
Prognosis
  • The recurrence rate with chondroblastoma alone is 20% at 3 years.
  • If the tumor has an aneurysmal component, the risk of recurrence is higher .
Complications
  • Recurrence
  • Joint stiffness
Patient Monitoring
  • Follow-up care is necessary because recurrence is common.
  • Radiographs should be repeated every 6-12 months after excision for ~2 years.
Miscellaneous
Codes
ICD9-CM
213.4 Chondroblastoma
 
Patient Teaching
  • Patients should be counseled that the lesion is benign and rarely metastasizes (<2%).
  • However, if the tumor is not removed, local morbidity may occur because of progressive enlargement of the involved epiphysis and destruction of the joint.
FAQ
Q: Is chemotherapy or radiation therapy needed for chondroblastoma?
A: Chondroblastoma is a benign bone tumor so there is no need for chemotherapy or radiation therapy.
 
Q: Is there any risk of getting a viral disease or hepatitis after curettage and bone grafting for a chondroblastoma?
A: In general, no risk exists. The graft materials are very safe in that all the cells and nonbone proteins are removed. The exception is fresh-frozen grafts, which have the same risk of viral transmission as a blood transfusion (~1 in 500,000).

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