This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Osseous Origin Bone Tumors, Subject name: Orthopaedics
Which is the commonest true benign bone tumor? 
Select and explain. 
A. Osteoid osteoma, B. Hemangioma, C. Osteochondroma, D. Enchondroma
A: Osteoid osteoma
Answer: A: Osteoid osteoma 
Explanation: Ans. is 'a' i.e.. Osteoid osteoma Important factso Commonest bone malignancieso Commonest primary' malignant tumoro Commonest primary malignant tumor of long bones---SecondariesMultiple myelomaOsteosarcomao Commonest benign tumor of bone-Osteochondroma(Osteochondroma is not true neoplasm since its growth stops with cessation of growth at the epiphyseal plate)o Commonest true benign tumor of bone-Osteoid osteomao Commonest benign tumor of hand-EnchondromaCommonest siteo Ivory osteoma-Frontal sinuso Osteoid osteoma-Tibiaa Admantinoma (Ameloblastoma)-Mandibleo Chordoma-Sacrum and cervical spineo Osteoclastoma-Lowrer end of femuro Ewing's sarcoma-Femur diaphysis > tibia diaphysiso Osteosarcoma-Distal femur (45%), Proximal tibia (25%)o Simple bone cyst-Proximal humeruso Aneurysmal bone cyst-Bones around knee (Femur, tibia)o Osteochondroma-Bones around knee (distal femur > proximal tibia)o Fibrous dysplasiao Enchondroma--Proximal femur > Tibia\Phalanges of hando Multiple myeloma-Vertebraeo Metastasis-Vertebrae