Cemento-Ossifying Fibroma of the Maxilla Mimicking a Malignant Chondroid-Matrix Tumor in a Young Adult Treated with Hemimaxillectomy: A Case Report and Review of the Literature

Cemento-ossifying fibroma (COF) is a benign fibro-osseous neoplasm of the jaws that predominantly occurs in the mandible, whereas maxillary lesions are less common and may exhibit more aggressive local behavior. Radiologically, these lesions can mimic malignant bone tumors, including chondrosarcoma and osteosarcoma, particularly when they exhibit extensive bone destruction and a chondroid-appearing matrix. This case report aimed to describe a young adult with a large right maxillary COF exhibiting computed tomography (CT) findings suggestive of malignancy, highlight the diagnostic approach, and discuss surgical management and the potential role of adjuvant radiotherapy. A 26-year-old man presented with a two-year history of painless right cheek swelling accompanied by nasal deviation, reduced olfaction, loosening of the right maxillary posterior teeth, and diplopia. Contrast-enhanced CT revealed a heterogeneous, hyperattenuating mass measuring 6.58 × 6.97 × 5.76 cm, with a chondroid-appearing matrix, arising from the wall of the right maxillary sinus. The lesion demonstrated erosion of the orbital floor and destruction of the zygomatic bone and maxillary alveolar process, raising suspicion of a primary malignant bone tumor. Incisional biopsy revealed a benign fibro-osseous lesion, while immunohistochemical staining was negative for MDM2 and showed no detectable Ki-67 labeling. The patient subsequently underwent right hemimaxillectomy through a Weber–Ferguson incision, and definitive histopathological examination confirmed ossifying fibroma without evidence of malignancy. No adjuvant therapy was administered, and postoperative local disease control was reported. This case highlighted the potential for large maxillary COF lesions to mimic malignant bone tumors on imaging, emphasizing the importance of integrating clinical, radiologic, and histopathologic findings, with adjunctive immunohistochemical assessment when indicated, to establish an accurate diagnosis and avoid unnecessary treatment. Complete surgical excision remained the primary treatment approach, while adjuvant radiotherapy was not indicated for histologically confirmed benign COF.