Osteofibrous dysplasia is a rare bone condition that primarily affects the long bones of the leg, most commonly the tibia (shin bone) and fibula (smaller bone in the calf), in children and adolescents. This benign condition does not spread to other parts of the body.
Understanding Osteofibrous Dysplasia
Osteofibrous dysplasia is a fibro-osseous lesion, consisting of fibrous tissue and immature bone. It develops in the outer layer, or cortex, of the affected bone, with the shin bone being the most frequent site. While it can occur in other long bones like the humerus, radius, or ulna, it is overwhelmingly found in the tibia and fibula.
The condition is most commonly observed in individuals under 20 years of age, with many cases detected in infancy and childhood, particularly before the age of 10. The exact cause of osteofibrous dysplasia remains unknown, but it is considered a developmental anomaly rather than an infection or injury. The lesion grows progressively until skeletal maturity, usually around 15 years of age, after which its growth slows or stops.
Recognizing and Diagnosing Osteofibrous Dysplasia
Osteofibrous dysplasia is discovered incidentally during imaging studies. It can also be identified after a pathological fracture, a break occurring in bone weakened by the condition. While many cases are asymptomatic, some individuals may experience localized pain, swelling, or a palpable mass.
Diagnosis involves imaging studies. X-rays can reveal characteristic eccentric, well-circumscribed osteolytic lesions with a sclerotic border, appearing lobulated or bubbly in the anterior cortex of the tibial diaphysis. Magnetic Resonance Imaging (MRI) provides a more detailed visualization of the lesion’s extent and tissue characteristics, showing intermediate signal intensity on T1-weighted images and intermediate to high signal on T2-weighted images. A definitive diagnosis requires a biopsy, where a tissue sample is taken for microscopic examination. This step is important for distinguishing osteofibrous dysplasia from other bone conditions, especially adamantinoma, a malignant tumor that can have a similar appearance on imaging.
Treatment Approaches for Osteofibrous Dysplasia
The management of osteofibrous dysplasia is tailored to individual factors such as the patient’s age, the lesion’s size and location, and the presence of symptoms or fracture risk. For smaller, asymptomatic lesions, particularly in younger children, a “wait and see” approach with regular follow-up imaging may be adopted. Some lesions can spontaneously regress after skeletal maturity is reached.
Surgical intervention is considered for persistent pain, significant fracture risk, or large lesions. Common surgical procedures include curettage, which involves scraping out the lesion from the bone. Following curettage, the resulting cavity is filled with bone graft material (from the patient, a donor, or synthetic) to restore mechanical stability. If a fracture has occurred or the bone is significantly weakened, internal fixation with rods or plates may be necessary to stabilize the bone.
Long-Term Outlook
The prognosis for individuals with osteofibrous dysplasia is favorable. However, local recurrence can occur after surgical treatment, particularly if the lesion was not entirely removed. Recurrence has been reported from 5 to 15 years after diagnosis, and sometimes even later, up to 24 or 36 years.
While osteofibrous dysplasia can weaken the affected bone, increasing the risk of pathological fractures (breaks that happen with minimal trauma). Ongoing medical monitoring and follow-up with orthopedic specialists are important to track the lesion’s behavior and manage any potential complications, such as bone deformity. With appropriate management, most individuals with osteofibrous dysplasia are able to lead normal, active lives.