Osteosarcoma can arise from:
Correct Answer: Metaphysis
Description: Ans. c (Metaphysis). (Ref. to Radiology Review Manual, 5th/138; Essential orthopedics by Maheshwari 2nd/218)OSTEOSARCOMA* It is 2nd most common 1deg malignant tumor of bone (after multiple myeloma). Peak incidence in menl0-20 years of age. * It has bimodal age distribution: 10-25 years and > 60 years with M:F = 3:2 to 2:1. * Commonly found in the metaphysis of longbones, often around distal femur, proximal tibial region (knee). * Predisposing factors include Paget's disease of bone, bone infarcts, radiation, and familial retinoblastoma. Codman's triangle or sunburst pattern (from elevation of periosteum) on x-ray. * MRI is preferred modality. Clearly defines marrow extent (best on T1W1), vascular involvement and soft tissue component (best on T2W1). Radionuclide bone scan (NUC) shows intensity increased activity on blood flow, blood pool, delayed images (hypervascularity, new bone formation). Doughnut sign (peripherally increased uptake with central photopenia on bone scan) is a classical feature. Poor prognosis. * Standard management: Preoperative chemotherapy followed by limb-sparing surgery followed by postoperative chemotherapy (Sandwich Therapy). * Rx:Osteosarcoma is radio- resistant; radiation therapy has no role in the routine management.Ewing's sarcomaAnaplastic small blue cell malignant tumor. Most common in boys < 15. Extremely aggressive with early mets, but responsive to chemotherapy. Characteristic "onion-skin" appearance in bone ("going out for Ewings and onion rings"). Commonly appears in diaphysis of long bones, pelvis, scapula, and ribs. 11;22 translocation.ChondrosarcomaMalignant cartilaginous tumor. Most common in men aged 30-60. Usually located in pelvis, spine, scapula, humerus, tibia, or femur. May be of 1deg origin or from osteochondroma. Expansile glistening mass within the medullary cavity
Category:
Orthopaedics
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