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Year |
2001 |
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Question Number |
86 |
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Category |
Select |
Question
A 24 year old man has had ankle pain for 1 year. Figures 21a through 21 d show AP and Lateral radiographs , an axial T1-weighted MRI scan and a biopsy specimen. What is the most likely diagnosis?
1. Nonossifying fibroma
2. chondroblastoma
3. giant cell tumor
4. aneurysmal bone cyst
5. telangiectactic osteosarcoma
Figures
Answer (click for answer)
The correct answer is 3. Giant cell tumor is one of the three principle tumors of unknown origin (the other two are Ewing’s and adamantinoma). The lesion is a benign but aggressive process. This benign tumor may rarely (<2%) metastasize to the lungs. The lesion is most common in epiphysis of long bones and about 50% of lesion occur about the knee, the vertebra and sacrum are involved in 10% of cases. Pt present with pain that is usually referable to the joint involved.
Radiographs show a purely lytic destructive lesion in the metaphysis. The cells are poorly differentiated and have round-to-oval or even spindle-shaped nucleus. Giant cell tumors may undergo a number of secondary degenerative changes such as aneurysmal bone cyst formation, necrosis, foam cell formation and reactive new bone. Treatment is aimed at removing the lesion with preservation of the involved joint. Extensive exteriorization (removal of a large cortical window over the lesion), curettage with hand and power instruments and chemical cauterization with phenol are performed. The defect is reconstructed with subchondral bone graft and methylmethacrylate.
Reference: Miller MD, Brinker MR: Review of Orthopeadics, 3rd edition, Pp420-424