This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bone Tumour, Subject name: Orthopaedics
Osteosarcoma can develop in: 
Select and explain. 
A. Osteoid osteoma, B. Osteoblastoma, C. Paget's disease, D. All of the above
C: Paget's disease
Answer: C: Paget's disease 
Explanation: Ans: c (Paget's disease) Ref: Maheswari, 4th ed,p. 221Osteosarcoma can develop secondary to premalignant diseases of the bone.They are usually less malignant & seen in the older age group.Premalignant lesions are:* Paget's disease* Diaphyseal aclasis* Enchondromatosis* Post radiation