This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ohopaedics Q Bank, Subject name: Orthopaedics
A 15 yr school going student complains of moderate amount of occasional pain and swelling over the right knee joint. X ray was done which shows a lesion in right femoral distal epiphysis is suggestive of: 
Select and explain. 
A. Enchondroma, B. Osteochondroma, C. Osteoclastoma, D. Chondroblastoma
D: Chondroblastoma
Answer: D: Chondroblastoma 
Explanation: Chondroblastoma and GCT are epiphyseal tumours. GCT occurs in 20-40th decade Chondroblastoma 8-16 years of age group . Mc site of chondroblastoma is epiphysis of the distal femur Xray - expansile, epiphyseal, slightly symmetrically expansile. Mimics synovitis C/F - pain and swelling. Biopsy :- Chicken wire calcification Rx curettage with bone grafting or bone curettage.