ATYPICAL RADIOGRAPHIC PRESENTATION OF OSSIFYING FIBROMA

Background History: A 21-year-old female presented with a 1-year history of pain in the mandibular right premolar region. Radiographic findings: The multidetector computed tomography (MDCT) images showed a 5 × 1.7 cm radiolucent lesion of the mandible extending from the left canine, across the midline, to the right second molar. There was thinning of the buccal and lingual cortices, with displacement of the buccal cortex. There was evidence of thin trabeculae in the buccal cortical area. There was displacement of the first and second premolars in the region, with evidence of resorption of the roots of the incisors and right first and second molars. The inferior alveolar canal was not visualized within the region of the lesion, and it was difficult to determine if there was displacement or destruction of the canal. Differential Interpretation: The differential interpretation included giant cell lesion, ameloblastoma, odontogenic keratocyst, and odontogenic myxoma. Microscopic Description: Microscopic examination revealed multiple, small, round to ovoid islands of demineralized osteoid and acellular basophilic material, scattered amidst a dense fibrocollagenous connective tissue, populated with bland, occasionally stellate, fibroblasts. Discussion/Conclusions The lesion was diagnosed as benign fibro-osseous lesion consistent with a cemento-ossifying fibroma. The MDCT images provided a challenging interpretation in this case. On the basis of the images, the more obvious diagnosis was toward a benign cyst or tumor, such as a giant cell lesion, with differential diagnoses of ameloblastoma, odontogenic keratocyst, or odontogenic myxoma. However, we should not rule out aggressive ossifying fibromas among the differential diagnoses as this case clearly proves with such typical features. History: A 21-year-old female presented with a 1-year history of pain in the mandibular right premolar region. Radiographic findings: The multidetector computed tomography (MDCT) images showed a 5 × 1.7 cm radiolucent lesion of the mandible extending from the left canine, across the midline, to the right second molar. There was thinning of the buccal and lingual cortices, with displacement of the buccal cortex. There was evidence of thin trabeculae in the buccal cortical area. There was displacement of the first and second premolars in the region, with evidence of resorption of the roots of the incisors and right first and second molars. The inferior alveolar canal was not visualized within the region of the lesion, and it was difficult to determine if there was displacement or destruction of the canal. Differential Interpretation: The differential interpretation included giant cell lesion, ameloblastoma, odontogenic keratocyst, and odontogenic myxoma. Microscopic Description: Microscopic examination revealed multiple, small, round to ovoid islands of demineralized osteoid and acellular basophilic material, scattered amidst a dense fibrocollagenous connective tissue, populated with bland, occasionally stellate, fibroblasts. The lesion was diagnosed as benign fibro-osseous lesion consistent with a cemento-ossifying fibroma. The MDCT images provided a challenging interpretation in this case. On the basis of the images, the more obvious diagnosis was toward a benign cyst or tumor, such as a giant cell lesion, with differential diagnoses of ameloblastoma, odontogenic keratocyst, or odontogenic myxoma. However, we should not rule out aggressive ossifying fibromas among the differential diagnoses as this case clearly proves with such typical features.