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).
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