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

Fibrosarcoma Epidemiology

 * 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

Natural History

 * 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

Diagnosis

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

Staging

 * Please see the bone staging page

Treatment Overview

 * 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