OBJECTIVE: To report the possible malignant transformation of primary sinonasal ameloblastoma into sinonasal ameloblastic carcinoma.

METHODS
Design: Case Report

Setting: Tertiary Public University Hospital

Patient: One

RESULT: A 50-year-old woman with a previous diagnosis of sinonasal ameloblastoma reported recurrence of symptoms of right-sided nasal obstruction and epistaxis two years after endoscopic sinus surgery. Clinical examination, CT scans and subsequent total maxillectomy with orbital exenteration revealed a left intranasal mass with maxillary, ethmoid and orbital floor extension and pulmonary and hepatic metastases.  Histopathologic findings of palisading columnar epithelium with reverse polarity with malignant features were consistent with ameloblastic carcinoma. Despite subsequent cycles of chemotherapy, the patient died two years after surgery. To the best of our knowledge, there have been no published reports of a primary sinonasal ameloblastoma with malignant transformation in the English literature.

CONCLUSION: Ameloblastic carcinoma is a rare neoplasm which may arise de novo or from malignant transformation of an ameloblastoma. Because ameloblastoma is commonly encountered in our setting, clinicians should be aware of this possibility and closely follow their patients accordingly.