<unk>  (fibroblastic sarcoma) is a malignant tumor derived from fibrous connective tissue and characterized by immature proliferating fibroblasts or undifferentiated anaplastic spindle cells.<unk>  is classified into 3 grades: low grade (differentiated), intermediate, and high grade (anaplastic).  There are 3 stages of<unk>  based on the grade and extent of the lesion.  The tumor may be localized at the end of the long bones. Most often it affects the upper end of tibia or lower end of femur.<unk>  is a rare disease that affects approximately one in two million people annually.  Patients of all age groups may develop<unk> , but are most common between the third and sixth decades of life.<unk>  is associated with a 5-year survival rate of 30% among patients with high grade medullary lesions and 50-80% among patients with surface<unk> s and low grade<unk> s.  Common risk factors for the development of<unk>  are preexisting benign lesions, radiation therapy, surgically treated fractures, and infarction of bone.  The most common symptoms of<unk>  include pain, swelling, loss of range of motion.<unk>  must be differentiated from other conditions that cause pain, swelling, and lesions that may appear similar to<unk>  on radiological imaging.
Fibrosarcoma
Chondrosarcoma
Fibroma
Liposarcoma
Dermatofibrosarcoma
Sarcoma
Elastofibroma
Soft tissue sarcoma