Non-ossifying fibroma

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC

Non-ossifying fibroma
Synonyms	Metaphyseal fibrous defect, fibrous cortical defect
Pronounce	N/A
Specialty	N/A
Symptoms	Usually asymptomatic, may cause pain or fracture if large
Complications	Pathological fracture
Onset	Typically in children and adolescents
Duration	Often resolves spontaneously
Types	N/A
Causes	Unknown, possibly developmental
Risks	None known
Diagnosis	X-ray, CT scan, MRI
Differential diagnosis	Fibrous dysplasia, Osteosarcoma, Chondromyxoid fibroma
Prevention	N/A
Treatment	Observation, surgical curettage if symptomatic
Medication	N/A
Prognosis	Excellent, often resolves without treatment
Frequency	Common in children, especially males
Deaths	N/A

A benign bone tumor

Non-ossifying fibroma (NOF) is a benign bone tumor that typically occurs in the metaphysis of long bones in children and adolescents. It is one of the most common benign bone lesions and is often discovered incidentally on X-rays taken for other reasons.

Pathophysiology

Non-ossifying fibromas are composed of fibrous tissue and are considered a type of fibrous cortical defect. They are characterized by a proliferation of spindle-shaped fibroblasts and histiocytes, often with scattered multinucleated giant cells. The lesion is typically well-circumscribed and located in the cortex of the bone.

Clinical Presentation

Most non-ossifying fibromas are asymptomatic and are found incidentally. However, larger lesions may cause pain or pathological fractures, especially if they weaken the structural integrity of the bone.

Diagnosis

Diagnosis is primarily made through imaging studies. On X-ray, non-ossifying fibromas appear as well-defined, eccentric, lytic lesions with a sclerotic margin. They are often located in the metaphysis of long bones such as the femur or tibia. Advanced imaging techniques such as CT scan or MRI can be used to further characterize the lesion. On CT, a mature non-ossifying fibroma may show a well-defined, cortically based lesion with a sclerotic rim.

Mature non-ossifying fibroma CT

Treatment

In most cases, non-ossifying fibromas do not require treatment and are monitored with periodic imaging. If the lesion is large or symptomatic, surgical intervention may be necessary. This can include curettage and bone grafting to stabilize the bone and prevent fracture.

Prognosis

The prognosis for non-ossifying fibroma is excellent. These lesions often spontaneously regress as the child grows, and they rarely cause long-term complications. Malignant transformation is extremely rare.

See also

• Bone tumor
• Fibrous dysplasia
• Osteochondroma