This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
True statements(s) regarding osteoid osteoma is/are -a) Malignantb) MC bone involvement-tibiac) Local excision or curettage cured) Bone pain relieved by aspirine) X-ray shows : density surrounding radiolucent lesion 
Select and explain. 
A. bde, B. ade, C. ace, D. bce
A: bde
Answer: A: bde 
Explanation: Osteoid osteoma is a benign tumor.
Most common site involved is diaphysis of Tibia.
Pain of osteoid osteoma is relieved by salycylates or other NSAIDs.
X-ray shows small radiolucent area (nidus) surrounded by dens sclerosis.
The only treatment is wide en block excision along with internal fixation with or without bone grafting.