osteoblastic sarcoma


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Related to osteoblastic sarcoma: osteogenic sarcoma

osteosarcoma

A high-grade sarcoma which arises in the metaphysis of long bones and produces malignant osteoid.

Epidemiology
Osteosarcomas comprise 2–3% of paediatric malignancies and 20% of all bone cancers; frequency 4–5/106 age range, 5–50 (60% under age 25), more common in males.

Clinical findings
Pain, swelling of extremity, pathological fractures.

Location
Metaphysis of long bones (distal femur, proximal tibia, proximal humerus); less commonly in flat bones, facial, pelvic, scapula, spine, short bones.

Predisposing factors
Usually arises de novo, but may be due to radiation, Paget’s disease of bone, linked to chemotherapy (alkylating agents), pre-existing benign bone lesions (fibrous dysplasia, osteochondromatosis, chondromatosis), foreign bodies (e.g. orthopaedic hardware).

Imaging
Variable sclerosis and osteolysis, Codman’s triangle.

Management
Pre-op chemotherapy; resect.

Metastases
Lungs, lymph nodes, other bones.

Prognosis
Very poor; better if 95% of the tumour is necrotic.

Osteosarcoma types
-Conventional
• Osteosarcoma NOS (not otherwise specified)
• Chondroblastic
• Fibroblastic (osteofibrosarcoma)
• Central osteosarcoma (conventional central osteosarcoma, medullary osteosarcoma)
• Intracortical osteosarcoma
-High-grade superficial
-Low-grade central
-Parosteal (juxtacortical)
-Periosteal (chondroblastic)
-Secondary
-Small cell
-Telangiectatic
-Microscopic variants
• Chondroblastic osteosarcoma
• Fibroblastic osteosarcoma
• Giant cell rich osteosarcoma
• Osteoblastic osteosarcoma (osteogenic osteosarcoma)
• Small-cell osteosarcoma
• Telangiectatic osteosarcoma