Fibrous Tumours

• Benign Fibrous Tumours


  • Non-ossifying fibroma
• Non-ossifying Fibroma Overview


  • Previously divided into:

  - Fibrous cortical defect - <2cm

  - Non-Ossifying Fibroma - >2cm

  • Age 8-20 years

  • M:F (2:1)

  • Mc in tibia

  • Can occur in any bone

  Features

  • Usually asymptomatic, clinically insignificant (Especially if small <2cm)

  • Can become large enough to weaken bone and fracture

  Differentials: Any benign soap bubbly lesion

  Treatment: Leave me alone lesion, will spontaneously regress

  Advanced imaging: Unnecessary
• Non-ossifying Fibroma Radiographic Features


  • Eccentric, lucent, geographic lesion with sclerotic margins

  • Occurs in the metaphysis/metadiaphysis

  • Primarily involves cortical bone

  • Can have endosteal scalloping and minimal bony expansion

  • Occasionally ground glass matrix

  • When they heal, they can become opaque
• Non-ossifying Fibroma


  Well defined sclerotic lesion in the metadiaphyseal region of the distal tibia.

  
• Non-ossifying Fibroma


  Well-defined lucent lesion, mildly expansile in the metadiaphyseal region of the tibia. Eccentric. Multiple septations

  
• Malignant Fibrous Tumours


  • Primary fibrosarcoma

  • Secondary fibrosarcoma
• Primary Fibrosarcoma Overview


  • Age 30-50 years

  • M:F (1:1)

  • Mc occurs at the knee

  • Metastasises via the lymph system

  Features:

  • Pain & local swelling of long duration

  • May present with pathologic fracture

  Differentials: Any malignant tumour, (Similar: malignant fibrous histiocytoma)

  Treatment: Amputation

  Advanced imaging: MRI for identifying and staging
• Primary Fibrosarcoma Radiographic Feature

  • Ill-defined, purely lytic medullary lesion

  • Very destructive, but usually very little periosteal reaction

  • Large soft tissue mass is characteristic

  • Mc origin metaphyseal

  • Lichtenstein’s Rule: Non-specific lytic destruction around the adult knee
• Secondary Fibrosarcoma Overview


  • Malignant degeneration of a previously benign process (Paget’s disease, fibrous dysplasia, & bone infarcts)
• Fibrosarcoma


  Agressive lesion. Cortical destruction. Long zone of transition. purely lytic. No calcification or sclerotic areas. Extending into the soft tissues.