<s>[INST] context: OSTEOSARCOMA : Classification * PRIMARY or SECONDARY * PRIMARY OSTEOSARCOMAS (15 - 25 yrs) Conventional /classic osteosarcoma (high grade, intra medullar y) Low-grade intramedullary osteosarcoma Paraosteal osteosarcoma Periosteal osteosarcoma High-grade surface osteosarcoma Telangiectatic osteosarcoma, and Small cell osteosarcoma. * SECONDARY OSTEOSARCOMAS * Osteosarcoma occurring at the site of another disease process. * more common in >50 years of age most commonly a/w premalignant condition like - Paget disease - Previous radiation treatment - endochondromatosis - Fibrous dysplasia - Osteochondromas - Osteogenesis imperfecta Clinical Presentation * Pain- progressive pain paicularly with activity. * Swelling - Palpable mass in the region of metaphysis. - skin over the swelling shiny with prominent veins. - swelling may be warm & tender. * Decreased range of motion of the involved joint. * Lymphadenopathy - unusual focal & regional lymph node involvement. * Respiratory finding - late stage with lung metastasis. * Fever & night sweats are rare. Treatment Radioloical staging Biopsy to confirm diagnosis Preo perat ivhemotherapy Repeat radiological staging (access chemo response, finalize surgical treatmeni Ian) Surgical resecting with wide margin Reconstruction using one of many techniques Post op chemo based on preop response ref : maheswari 9th ed [/INST] question: A young girl presented with swelling of right thigh, with history of trauma 2 months back. Now she presents with swelling at mid-shaft of femur & low grade fever. ESR is mildly raised. X-ray shows a laminated periosteal reaction. Next line of investigation would be - | options: A: MRI B: Biopsy C: Bone scan D: Blood count & CRP | answer: A </s>