Cemento-ossifying fibroma of the mandible associated with cervical tooth resorption and apparent communication with the pulp space: a case report

Cemento-ossifying fibroma (COF) is a benign mesenchymal odontogenic tumor that typically arises in tooth-bearing areas of the jaws. Most lesions are well circumscribed and slow growing, although tooth displacement and root resorption may occur. Apparent communication between a COF-associated cervical resorptive defect and the pulp space is unusual and may raise concern for a locally aggressive odontogenic lesion or jaw malignancy. This case highlights an uncommon pattern of dental hard-tissue destruction and the importance of clinicoradiologic and histopathologic correlation. A 35-year-old woman presented with a painless, gradually enlarging swelling in the left posterior mandible of six months’ duration. Intraoral examination showed buccal swelling adjacent to the left mandibular first molar, pink discoloration of the crown, cervical resorption and no response to cold pulp testing (electric pulp test value: 80 vs. 35 on the contralateral control tooth). Cone-beam computed tomography demonstrated an expansile lesion with buccal cortical thinning and an irregular cervical resorptive defect of tooth 36 that reached and appeared to communicate with the pulp chamber. Wide local excision of the mandibular lesion and extraction of the affected tooth were performed. Histopathologic examination of the excised lesional tissue supported the diagnosis of COF. The bland morphology, absence of malignant histologic features, and low Ki-67 labeling index supported a benign lesion. MyoD1 staining was negative; focal weak nuclear MDM2 staining and faint cytoplasmic CDK4 staining without convincing nuclear immunoreactivity were considered nondiagnostic. The surgical site healed well, and no clinical or radiographic recurrence was observed during 15 months of follow-up. The patient subsequently underwent dental implant placement, restoring masticatory function. COF should be considered in the differential diagnosis of jaw lesions associated with marked cervical tooth resorption and apparent communication with the pulp space. Because the extracted tooth was not examined using decalcified serial sections, the precise mechanism of this apparent communication could not be definitively established. Accurate diagnosis requires careful correlation of clinical, imaging, and histopathologic findings, and long-term follow-up is warranted.