Review Question - QID 4633

The above clinical vignette and radiograph in figure A are consistent with a nonossifying fibroma. Observation is the most appropriate treatment.

Nonossifying fibromas are the most common benign bone tumors in childhood commonly affecting children 5-15 years old. They most commonly occur in the metaphysis of long bones, and 80% occur in lower extremity. Common locations include the knee (distal femur and proximal tibia) and distal tibia.

Biermann et al. review the clinical presentation, imaging, and contemporary management of the most common childhood tumors including: nonossifying fibroma, unicameral bone cyst, aneurysmal bone cyst, fibrous dysplasia, and exostosis.

Betsy et al. reviewed the identification, workup, and management of nonossifying fibromas and fibrous cortical defects. They suggest that small, asymptomatic lesions can be followed with serial radiographs. Larger lesions or those that are concerning for pathologic fracture can be treated with incisional biopsy, curettage, and bone grafting. Pathologic fractures involving such lesions should be treated with cast immobilization until the fracture has healed, followed by biopsy, curettage, and bone grafting.

Figure A is a radiograph showing a typical NOF. Notice the metaphyseal eccentric "bubbly" lytic lesion surrounded by a sclerotic rim.

Incorrect Answers:
Answers 1+2: Enchondroma commonly has a "popcorn" mineralization in the metaphysis of bones, and are treated with observation.
Answer 4: Nonossifying fibroma is routinely treated with observation.
Answer 5: Aneurysmal bone cyst is a benign and non-neoplastic reactive bone lesion filled with multiple blood-filled cavities. Benign lesion can be observed, but aggressive lesions are treated with curettage and bone grafting.