Giant Cell Tumor (GCT)

Giant Cell Tumor (GCT)

Prepared by Dr. Ahmet Mucteba YILDIRIM

GCBT is an aggressive benign bone tumour, classified as intermediate (locally aggressive) in the 2020 WHO classification.
Accounts for 5–10% of all primary bone tumours.
Typically affects individuals aged 20–40 years.
Female > Male (1.3–2:1).
Associated conditions: Noonan syndrome, Paget’s disease.

Common Sites

• Most common: Knee region (distal femur, proximal tibia)
• Also seen in: Distal radius, proximal humerus, sacrum (most common axial site)

 Clinical Presentation

• Persistent pain (most common)
• Joint swelling, limited motion, or pathological fracture (5–10%)
• Palpable mass (if soft tissue extension exists)
• No constitutional symptoms

 Imaging Features

X-ray:

• Eccentric, lytic lesion
• No sclerotic rim, no calcification
• Cortical expansion without periosteal reaction
• Wide transition zone in fibula/ulna
• Aggressive signs: Geographic destruction, soft tissue mass, fluid-fluid levels (if secondary ABC)

CT:

• Detects lung metastases, evaluates axial involvement and trabecular pattern

MRI:

• T1: Hypo- to isointense
• T2: Hyperintense, heterogeneous
• Shows soft tissue extension and blooming on GRE (hemosiderin)

 Campanacci Classification

Used as a surgical guide.

 Differential Diagnosis

• Chondroblastoma: Epiphyseal, sclerotic rim, surrounding bone marrow oedema
• Aneurysmal Bone Cyst (ABC): May co-exist, lacks soft tissue mass
• Brown Tumour: Consider if high PTH

    Treatment

Surgical Management (Extremities)

• Intralesional curettage + adjuvant (phenol, ethanol, cryotherapy, argon gas, high-speed burr) + PMMA or graft
  PMMA advantages: Exothermic necrosis, easier recurrence detection
  Risks: Subchondral damage → early osteoarthritis
• Wide resection: Indicated in Campanacci 3, distal ulna/proximal fibula
• Denosumab (pre-op): Used to shrink tumour for limb-salvage surgery in Campanacci 3

 Management of Pelvic & Axial GCBTs

• Surgery carries high local complication risk
• Grade 1–2: Intralesional resection after radioembolization
• Grade 3:
  If feasible → Wide resection ± radioembolization
  If unresectable → Denosumab alone
• Radiotherapy: Only for inoperable cases (malignant transformation risk)

  Medical Therapy

Denosumab (RANKL inhibitor):

• Pre-op or in inoperable patients
• Avoid in Grade 1–2: Can reduce curettage efficacy and increase recurrence
• Risks: Malignant transformation with long-term use, osteonecrosis of jaw

Bisphosphonates (e.g., zoledronic acid):

• Reduces tumour size
• Side effects: ONJ, atypical femur fracture, oesophagitis, hypo-/hypercalcemia

 Metastasis & Complications

• Lung metastases: Typically indolent; metastasectomy for progressive disease
• Recurrence: 20–50% within 3 years, higher in axial/distal radius sites
• Malignant transformation: Rare but severe (e.g., UPS or osteosarcoma, linked to denosumab)
• PMMA-induced osteoarthritis due to chondral necrosis

 References

• Siegel, G. W., & Biermann, J. S. Orthopaedic Knowledge Update®: Musculoskeletal Tumors 5
• Kang, H. S., et al. Oncologic Imaging: Bone Tumors, Springer
• Choi, J. H., & Ro, J. Y. 2020 WHO Classification of Bone Tumors
• Bayram, S., et al. EFORT Open Rev, 2024;9(3):181–189