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
Aspirin is useful in which type of bone tumor: 
Select and explain. 
A. Osteonecrosis, B. Osteopetrosis, C. Osteoid osteoma, D. Ewing sarcoma
C: Osteoid osteoma
Answer: C: Osteoid osteoma 
Explanation: Ans. (c) Osteoid osteomaRef: Maheshwari 5th ed. / 235* Osteoid osteoma is a benign bone tumour characterized by pain which is relieved by non-steroidal anti- inflammatory drugs (NSAIDs), such as aspirin.* To clarify the mechanism of the pain, five osteoid osteomas were studied immune-histochemically using polyclonal antibodies against prostaglandin E2 (PGE2), S-100 protein and protein gene product.