This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2019, Subject name: Orthopaedics
What to be done next? 
Select and explain. 
A. Extended curettage with allograft, B. Bone biopsy, C. Curettage, D. Extended curettage with autograft
B: Bone biopsy
Answer: B: Bone biopsy 
Explanation: The given image shows a lytic area in the lower end of femur which extends up to the joint. The findings show Giant cell tumor , the only tumour which goes till the joint. The treatment of choice - extended curettage with autograft. To confirm GCT, bone biopsy is done next as histology is diagnostic.