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oncology

Giant Cell Tumor of Bone (GCT)

advanced
6 min
28 marks
6 questions
Clinical Scenario
A 28-year-old woman presents with 4 months of right knee pain and swelling. The pain is worse with weight-bearing and she has noticed increasing stiffness. She has no systemic symptoms. On examination, there is a palpable swelling at the proximal tibia, tenderness, and reduced knee range of motion. X-ray shows a lytic lesion extending to the subchondral bone of the proximal tibia. Laboratory tests are normal.
AP and lateral radiographs of the right knee showing a giant cell tumor of the proximal tibia. There is an eccentric, lytic lesion extending to the subchondral bone (epiphyseal-metaphyseal) with well-defined but non-sclerotic margins. No matrix calcification. The lesion abuts the articular surface, which is characteristic. MRI shows cystic change with fluid-fluid levels (secondary aneurysmal bone cyst component).
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AP and lateral radiographs of the right knee showing a giant cell tumor of the proximal tibia. There is an eccentric, lytic lesion extending to the subchondral bone (epiphyseal-metaphyseal) with well-defined but non-sclerotic margins. No matrix calcification. The lesion abuts the articular surface, which is characteristic. MRI shows cystic change with fluid-fluid levels (secondary aneurysmal bone cyst component).

Image source: Open Access medical literature (NIH/PubMed Central) • CC-BY License

Questions

Question 1 (4 marks)

Describe the clinical and radiographic features of GCT.

Question 2 (5 marks)

What is the histopathology and differential diagnosis?

Question 3 (6 marks)

Describe the surgical treatment options and adjuvants.

Question 4 (5 marks)

What is the role of denosumab in GCT management?

Question 5 (4 marks)

Discuss recurrence and pulmonary metastases.

Question 6 (4 marks)

What are the special situations in GCT management?

Exam Day Cheat Sheet

Must Mention

  • •Age 20-40, skeletally mature
  • •Epiphyseal-metaphyseal, extends to subchondral bone
  • •Eccentric lytic, no sclerotic rim, no matrix
  • •Mononuclear stromal cell = neoplastic
  • •Giant cells = reactive (RANK-expressing)
  • •Denosumab = RANK-L inhibitor

Common Pitfalls

  • •Wrong age (needs closed physis)
  • •Confusing with ABC
  • •Missing adjuvant concept
  • •Wrong neoplastic cell
  • •Not knowing denosumab
  • •Fearing lung mets excessively