Ossifying fibroma
Updates to Article Attributes
Ossifying fibromas (OF),also commonly referred to as osteofibrous dysplasia (OFD),especially when in the extremities, are benign bone lesions that should be differentiated from non-ossifying fibromas and fibrous dysplasia.
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
RadiographPlain radiograph and CT
-
seen as awell-circumscribed lesion -
demonstratesevidence 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
-<li>mandible and maxilla: these are examples of cementum-poor <a href="/articles/cemento-ossifying-fibroma">cement-ossifying fibromas</a> <sup>2</sup> (see <a href="/articles/odontogenic-tumours-classification-who-1992">WHO classification scheme for odontogenic tumours</a>)</li>- +<li>mandible and maxilla: these are examples of cementum-poor <a href="/articles/cemento-ossifying-fibroma">cement-ossifying fibromas</a> <sup>2</sup> (see <a href="/articles/2005-who-histological-classification-of-odontogenic-tumours">WHO classification scheme for odontogenic tumours</a>)</li>
-</ul><h4>Radiographic features</h4><h5>Radiograph and CT</h5><ul>-<li>seen as a well-circumscribed lesion</li>-<li>demonstrates evidence of intracortical osteolysis with a characteristic sclerotic band (osteoblastic rimming)</li>- +</ul><h4>Radiographic features</h4><h5>Plain radiograph and CT</h5><ul>
- +<li>well-circumscribed lesion</li>
- +<li>evidence of intracortical osteolysis with a characteristic sclerotic band (osteoblastic rimming)</li>
-<li><a title="Causes of lower limb bowing" href="/articles/leg-bowing-in-children">limb bowing</a></li>- +<li><a href="/articles/leg-bowing-in-children">limb bowing</a></li>
References changed:
- 7. Pathology And Genetics of Tumours of the Head And Neck. World Health Organization. ISBN:9283224175. <a href="http://books.google.com/books?vid=ISBN9283224175">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/9283224175">Find it at Amazon</a><span class="auto"></span>
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