Ameloblastic carcinoma is a rare odontogenic neoplasm that exhibits malignant histological features in primary and secondary tumours. This is a case of a 36-year-old woman who presented a hard mass in the right inferior jaw, associated with pain and gingival bleeding. The radiography showed a unilocular radiolucent lesion with sclerotic borders, resembling a benign tumour. After the anatomical-pathological diagnosis of ameloblastic carcinoma, the patient treatment consisted of surgical partial resection of the mandible, neck dissection, followed by reconstruction with a titanium plate. Post-operative radiotherapy was performed. The diagnosis of ameloblastic carcinoma remains a challenge and this tumour may require extensive surgical sampling or its total removal to establish the histological diagnosis.