Giant Cell Sarcoma

Definition

  • Also called giant cell sarcoma
  • High grade sarcoma arising with GCTB
  • Distinct from benign GCTB
  • Distinct from benign metastasising GCTB, which has histologically benign lung deposits

Classification

TypeDescription
PrimaryHigh grade sarcoma coexisting with conventional GCTB at first presentation
SecondarySarcoma at the site of previously treated GCTB, more common than primary
  • Most secondary cases follow radiotherapy, after a latent period of several years
  • A smaller group arise after surgery alone, sometimes after multiple local recurrences
  • Sarcomatous change reported on denosumab, so atypical radiological change on denosumab warrants biopsy

Epidemiology

  • Rare, a small percentage of all giant cell tumours
  • Patients older than in conventional GCTB
  • Secondary cases present years to decades after initial treatment
  • Sites mirror GCTB, with distal femur, proximal tibia, distal radius and sacrum

Pathology

Histology of a high grade malignant tumour with bizarre tumour giant cells
Histology of a high grade malignant tumour with bizarre tumour giant cells. Image by Department of Pathology, Calicut Medical College, Wikimedia Commons, CC BY-SA 4.0.
  • Sarcoma is usually high grade osteosarcoma, fibrosarcoma or undifferentiated pleomorphic sarcoma
  • Primary cases show conventional GCTB alongside the sarcoma
  • Benign precursor may be absent in secondary cases
  • H3F3A G34W mutation confirms origin from GCTB

Clinical Features

  • New or increasing pain at a treated GCTB site
  • Rapidly enlarging mass or pathological fracture
  • Prior radiotherapy to the region

Investigations

  • Radiographs show aggressive lysis, cortical destruction, ill defined margins and soft tissue mass
  • Lesion may arise adjacent to prior graft or cement
  • MRI for local extent, CT chest and bone scan or PET for staging
  • Biopsy at a sarcoma centre along the future resection tract

Differential Diagnosis

  • Local recurrence of benign GCTB
  • Giant cell rich osteosarcoma
  • Brown tumour of hyperparathyroidism
  • De novo undifferentiated pleomorphic sarcoma

Management

  • Treated as high grade bone sarcoma
  • Neoadjuvant and adjuvant chemotherapy in suitable patients
  • Wide resection with endoprosthetic or biological reconstruction
  • Amputation when a wide margin with a functional limb is not achievable
  • Radiotherapy has a limited role given frequent post radiation aetiology

Prognosis

  • Poor, similar to or worse than other high grade bone sarcomas
  • Secondary and post radiation cases fare worse than primary cases
  • Pulmonary metastases are the usual cause of death

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.