Ossifying fibroma

Last revised by Assoc Prof Frank Gaillard on 30 May 2021

Ossifying fibromas are benign bone lesions that should be differentiated from non-ossifying fibromas and fibrous dysplasiaOsteofibrous dysplasia is considered as a separate pathological entity in view of its different presentation and treatment, although histopathologically similar to ossifying fibroma. 

These lesions are most frequently encountered in young children (often <10 years).

They comprise 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.

  • 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 cemento-ossifying fibromas 2 (see WHO classification scheme for odontogenic tumors)
  • sinonasal: expansile lesions with peripheral ossification and central lucency
  • well-circumscribed lesion
  • evidence of intracortical osteolysis with a characteristic sclerotic band (osteoblastic rimming)
  • moderate cortical expansion
  • homogeneous lesion matrix

Reported signal characteristics include

  • T1: low signal
  • T2: iso-high signal
  • T1 C+ (Gd): typically shows enhancement

Tend to regress over time. For locally aggressive lesions, surgical resection is often curative although recurrence has been reported.

Imaging differential considerations include

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Cases and figures

  • Case 1
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  • Case 2: mandibular
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  • Case 3: ethmoidal
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  • Case 4
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  • Case 5: sinonasal ossifying fibroma
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