A 50-year-old woman with a previous diagnosis of ameloblastoma was referred to the School of Dentistry Brazil complaining of a symptomatic lesion in the body and ramus mandibular. Her medical history was unremarkable. The intraoral examination demonstrated an exophytic tumor mass in the right posterior alveolar ridge. Computed tomography revealed a lesion with irregular margins extending from first premolar to distal to second molar of the left side of the mandible. A provisional diagnosis of recurrent ameloblastoma was considered, and an incisional biopsy was performed. Histopathologic evaluation of the specimen showed nests, follicles, and cords of epithelial clear cells. In occasional follicles the central cells showed a reticulum-like pattern, and some central cells showed keratinization. Peripheral cells presented palisading and reverse nuclear polarity. Necrosis, cellular, and nuclear pleomorphism were also observed. Final diagnosis of clear cell odontogenic carcinoma was established. The patient was referred for treatment and is being followed up.