Radiation Oncology/Sarcoma/Fibrosarcoma

Fibrosarcoma

Benign Fibrous Histologies

Nodular fasciitis: rapid growth over several weeks, pain, tenderness. Plump mature fibroblasts. Self-limiting process; recurrence uncommon after excision
Fibroma: nonspecific term. Dense fibrous nodule. Simple excision
Elastofibroma: rare, slow-growing benign tumor. Typically lower portion of the scapula. Repetitive manual tasks. Considered reactive lesions. Swollen eosinophilic collagen and elastic fibers. Simple excision
Superficial fibromatosis: arise from fascia or aponeuroses, small and slow growing
- Palmar fibromatosis (Dupuytren's contracture) most common
- Penile fibromatosis (Peyronie's disease) relatively rare, though more common in men who have palmar fibromatosis
Deep fibromatosis: clinically diverse, deep-seated fibrous neoplasms
- For more detail, please see the Desmoid tumor page

2-6% of primary malignant bone lesions
Arise most commonly in tubular long bones, usually femur or tibia
Most patients are 30-70; equal men and women
Predisposing factors (~30% cases) include Paget's, fibrous dysplasia, osteomyelitis, bone infarcts, bone cysts, benign giant cell tumors, desmoplastic fibromas, or previous RT treatment

Locally aggressive
Metastatic potential related to grade
- High grade similar to osteosarcoma: 5-year OS ~25%
- Low grade: 5-year (and 10-year) OS ~50%. Mets rate 5-15%
Survival: 5-year 34%, 10-year 28%, 20-year 25%
Children have relatively milder prognosis

Lytic with no reactive sclerosis
High grade lesions show cortical destruction and periosteal reaction; sometimes with soft-tissue mass
Radiographically very similar to osteosarcoma

Aggressive surgical resection
Not considered highly radiosensitive, but RT recommended for inoperable tumors, residual disease, and palliation
Perez (4th ed) recommends doses 66-70Gy with shrinking-field technique