Ossifying fibroma
Updates to Article Attributes
Ossifying fibromas (OF),also commonly referred to as osteofibrous dysplasia (OFD),especially when in the extremities,
Epidemiology
These lesions are most frequently encountered in young children (often <10 years).
Pathology
Histology
They comprise of haphazardly distributed lamellated bony spicules on a background of fibrous stroma. Despite being benign, they can be locally aggressive. Immunohistochemical staining of lesions shows positive keratin cells in the majority of the cases.
Location
- lower extremity
- tibia: most frequent site 5 (90% of the time); there is a predilection for the anterior tibial cortex
- femur: occurs in a diaphysial location
- mandible and maxilla: these are examples of cementum-poor cement-ossifying fibromas 2 (see WHO classification scheme for odontogenic tumours)
- sinonasal: expansile lesions with peripheral ossification and central lucency
Radiographic features
Plain radiograph and CT
- well-circumscribed lesion
- evidence of intracortical osteolysis with a characteristic sclerotic band (osteoblastic rimming)
- moderate cortical expansion
- homogeneous lesion matrix
MRI
Reported signal characteristics include
- T1: low signal
- T2: iso-high signal
- T1 C+ (Gd): typically shows enhancement
Treatment and prognosis
Tend to regress over time. For locally aggressive lesions, surgical resection is often curative although recurrence has been reported.
Complications
Differential diagnosis
Imaging differential considerations include
- fibrous dysplasia: has no osteoblastic rimming
- adamantinoma: may share a common origin with ossifying fibromas
- osteoid osteoma
- Osteofibrous dysplasia
-<p><strong>Ossifying</strong><strong> fibromas (OF)</strong>,<strong> </strong>also commonly referred to as <strong>osteofibrous dysplasia (OFD)</strong>,<strong> </strong>especially when in the extremities, are benign bone lesions that should be differentiated from <a href="/articles/non-ossifying-fibroma-1">non-ossifying fibromas</a> and <a href="/articles/fibrous-dysplasia">fibrous dysplasia</a>.</p><h4>Epidemiology</h4><p>These lesions are most frequently encountered in young children (often <10 years).</p><h4>Pathology</h4><h5>Histology</h5><p>They comprise of haphazardly distributed lamellated bony spicules on a background of fibrous stroma. Despite being benign, they can be locally aggressive. Immunohistochemical staining of lesions shows positive keratin cells in the majority of the cases.</p><h5>Location</h5><ul>- +<p><strong>Ossifying</strong><strong> fibromas (OF)</strong><strong> </strong>are benign bone lesions that should be differentiated from <a href="/articles/non-ossifying-fibroma-1">non-ossifying fibromas</a> and <a href="/articles/fibrous-dysplasia">fibrous dysplasia</a>. <a title="Osteofibrous Dysplasia" href="/articles/osteofibrous-dysplasia-1">Osteofibrous dysplasia</a> is considered as a separate pathological entity in view of different presentation and treatment, although histopathologically similar to ossifying fibroma. </p><h4>Epidemiology</h4><p>These lesions are most frequently encountered in young children (often <10 years).</p><h4>Pathology</h4><h5>Histology</h5><p>They comprise of haphazardly distributed lamellated bony spicules on a background of fibrous stroma. Despite being benign, they can be locally aggressive. Immunohistochemical staining of lesions shows positive keratin cells in the majority of the cases.</p><h5>Location</h5><ul>
-<a href="/articles/adamantinoma-of-long-bones">adamantinoma</a>: may share a common origin with ossifying fibromas</li>- +<a href="/articles/adamantinoma">adamantinoma</a>: may share a common origin with ossifying fibromas</li>
- +<li><a title="Osteofibrous Dysplasia" href="/articles/osteofibrous-dysplasia-1">Osteofibrous dysplasia</a></li>