Osteosarcoma may be the result of malignant transformation of mesenchymal stromal cell and characterised by direct formation of osteoid or bone. They are morphologically heterogenous with histological diversity. They can therefore be classified be cla...
Osteosarcoma may be the result of malignant transformation of mesenchymal stromal cell and characterised by direct formation of osteoid or bone. They are morphologically heterogenous with histological diversity. They can therefore be classified be classified into fibroblastic (spindle cell predominant), osteoblastic (bone predominant), chondroblastic (cartilage or chondroid differentiation) or telangiectatic (vascular differentiation). This heterogenicity may reflect the various developmental stages of single cell strain or the mutation of single cell. Being cancer cell, they have escaped from normal cell cycle regulation. They invade and colonise territories with unregulated growth. They have predilection site in metaphyseal of long bone(e.g. distal femur and proximal humerus) arising de no-va as primary osteosarcoma of secondary to pre-existing conditions (Paget's disease, multiple enchondroma, bone infarct, bone irradiation, etc). They can also occur in extraskeletal tissue. The tissue that have high growth and reparative process appear to form an excellent environment or "soil" for the invasive osteosarcoma to develop with its uncontrolled growth and ultimately metastases to other organs.