Incidence of Bilateral versus Unilateral Non-Ossifying Fibroma
Non-ossifying fibromas (NOFs) are overwhelmingly unilateral lesions, with bilateral or multiple presentations being exceedingly rare and typically associated with Jaffe-Campanacci syndrome. 1
Epidemiology and Laterality
- NOFs are solitary, unilateral lesions in the vast majority of cases, presenting as single eccentric metaphyseal defects in long bones 1, 2
- The estimated prevalence of NOFs in normal children ranges from 30-40%, but these represent predominantly single, unilateral lesions 2
- Bilateral or multiple NOFs are exceptionally uncommon and when present, should raise suspicion for Jaffe-Campanacci syndrome 1
Multiple NOF Presentations
When multiple NOFs do occur, specific patterns emerge:
- In one case series of 44 patients with 47 NOF lesions, only 3 cases (6.8%) had NOFs in multiple anatomical locations: one case with femur and fibula involvement, and two cases with femur and tibia involvement 3
- Multiple lesions with bilateral symmetry in the lower extremities suggest developmental bone defects rather than true neoplasms 3
- The presence of multiple NOFs at different sites is a hallmark feature distinguishing Jaffe-Campanacci syndrome from typical solitary NOF 1
Jaffe-Campanacci Syndrome
- This syndrome represents the rare presentation of multiple NOFs and includes systemic and dermal findings resembling Type 1 neurofibromatosis 1
- Patients present with typical non-ossifying fibromatous tumors but in multiple sites, distinguishing this from the common solitary presentation 1
Clinical Implications
- When encountering bilateral or multiple NOFs, clinicians should evaluate for associated systemic features of Jaffe-Campanacci syndrome, including café-au-lait spots, mental retardation, hypogonadism, and ocular abnormalities 1
- The typical NOF patient presents with a single asymptomatic lesion discovered incidentally on radiographs, most commonly in the distal femoral or proximal tibial metaphysis 1, 2, 4