Non Ossifying Fibroma

  • Etiology: Benign
  • Imaging:
    — Location: Diaphysis or metaphysis, along axis of bone, around knee and distal tibia
    — Lytic or blastic: Lytic with thin sclerotic rim and becomes sclerotic as they heal
    — Matrix: Fibrous
    — Zone of transition: Narrow
    — Periosteal new bone or cortical destruction: None
    — Additionally: Cortically based but can look central when large, early is lucent and geographic with thin sclerotic margin, late is sclerotic and then remodels to normal, classically eccentric expansile lucent lesion with bubbly and sclerotic border and as patients grow older lesions heal and become sclerotic before completely resolving
  • DDX:
  • Complications: Common cause of pathological fracture especially if large in size
  • Treatment: Self-resolving
  • Clinical:
    — Most common lucent lesion of pediatric bone
    — Rare in pelvis and other lesions should be considered first in pelvis

Radiology Cases of Non Ossifying Fibroma

Radiograph and CT of non ossifying fibroma
AP radiograph of the ankle (left) shows a metaphyseal lesion that is lucent with a thin sclerotic rim, a narrow zone of transition, and no periosteal reaction. The lesion is seen on coronal CT without contrast of the ankle (right) to be cortically based.
Radiograph of fibrous cortical defect of the tibia
AP radiograph of the ankle shows a metadiaphyseal lesion that is lytic and within the cortex with a narrow zone of transition and a sclerotic rim and no periosteal reaction.

Radiology Cases of Non Ossifying Fibroma With Pathologic Fracture

Radiograph of a pathologic fracture through a fibrous cortical defect
AP and lateral radiographs of the distal femur show a thin linear lucency running obliquely through a large, lucent, well corticated lesion in the femoral metaphysis.

Radiology Cases of Multiple Non Ossifying Fibromas in Jaffe Campanacci Syndrome in Neurofibromatosis Type I

Radiograph of multiple non ossifying fibromas in Jaffe Campanacci Syndrome
AP and lateral radiographs of the knee show multiple lucent lesions with thin sclerotic margins in the metaphysis of the femur, tibia and fibula.