Ossifying fibroma of the maxilla.

Ossifying fibroma is a benign fibro-osseous lesion that commonly involves the maxilla. (1) We evaluated a 57-year-old woman who complained of localized pain in the right maxillary area. Computed tomography (CT) detected a fibro-osseous lesion that proved to be an ossifying fibroma (figure).

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Included in the group of benign fibro-osseous lesions are fibrous dysplasias and ossifying fibromas. Although these two lesions are considered to be separate entities, they may not be distinguishable on histopathologic evaluation. Ossifying fibromas may have features that are characteristic of fibrous dysplasias (e.g., woven bone without osteoblastic rimming), and fibrous dysplasias may have histologic features that are consistent with ossifying fibromas (e.g., lamellar and osteoblastic rimming). Therefore, imaging correlation is important; otherwise, such lesions are designated as benign fibro-osseous lesions. (2)

Ossifying fibromas occur predominately in women, frequently during the third and fourth decades of life. Orbital and maxillary involvement is generally asymptomatic, but associated pain or swelling may be present. These lesions are occasionally identified as an incidental finding. (3) The lesion's CT features depend on its stage of development and the amount of mineralized matrix that is present. Lesions generally appear as well-circumscribed masses with smooth margins.

In its early stage, a lesion may appear as a solitary radiolucent cyst-like mass with minimal or absent internal calcified components; in its late stage, the lesion is radiodense. (1,3) On magnetic resonance imaging, ossifying fibromas appear to be heterogenous. They reflect an intermediate signal intensity on T1-weighted imaging and a hypointense signal intensity on T2-weighted imaging with moderate enhancement following intravenous administration of contrast on T1-weighted imaging. (1)

References

(1.) Mafee MF, Yang G, Tseng A, et al. Fibro-osseous and giant cell lesions, including brown tumor of the mandible, maxilla, and other craniofacial bones. Neuroimaging Clin N Am 2003;13:525-40.

(2.) Waldron CA, Giansanti JS. Benign fibro-osseous lesions of the jaws: A clinical-radiologic-histologic review of sixty-five cases. II. Benign fibro-osseous lesions of periodontal ligament origin. Oral Surg Oral Med Oral Pathol 1973;35:340-50.

(3.) Cheng C, Takahashi H, Yao K, et al. Cemento-ossifying fibroma of maxillary and sphenoid sinuses: Case report and literature review. Acta Otolaryngol Suppl 2002;(547):118-22.