Review Question - QID 217503

This radiographic lesions is suggestive of a Non-Ossifying Fibromas (NOF). The recommended treatment for this patient is observation.

NOFs are benign fibrogenic lesions that result from dysfunctional ossification that are most commonly found in the metaphysis of long bones. Patients typically present between the ages of 5 and 15 with an asymptomatic lesion discovered incidentally on radiographs. Diagnosis is made on radiographs with a characteristic metaphyseal, eccentric "bubbly" lytic lesion surrounded by a sclerotic rim. Treatment is observation as most lesions resolve spontaneously and progressively re-ossify as the patient enters 2nd and 3rd decade of life.

Herget et al. reviewed the radiological morphology of the NOF. They describe the life span according to the Ritschl-stages in an effort to determine critical stages with regard to pathological fractures and discuss the need for follow-up. They reported that the NOF follows a characteristic radiomorphological course with variable duration of each stage, with stage B lesions found to be at an increased risk of fracture. They concluded that follow-up, including clinical survey and imaging, at six to twelve month intervals may therefore be considered in the case of larger stage B lesions until stage C is reached.

Hudson et al. reviewed fibrous lesions. They reported that many benign fibrous lesions, including NOFs have typical radiographic appearances and many do not require advanced imaging. They concluded that these lesions are usually self-limited and can be managed with serial observation.

Figure A is the radiograph of the ankle that demonstrates an NOF of the distal lateral tibia.

Incorrect Answers:
Answer 2: Cast immobilization is indicated with pathologic fractures
Answer 3: Curettage and bone grafting is indicated with symptomatic and large lesion (> 50-75% cortical involvement)
Answer 4: Prophylactic stabilization is not indicated in a non-symptomatic NOF
Answer 5: This is a benign lesion that typically resolves spontaneously and is not indicated for an open biopsy.