Ameloblastoma is an odontogenic tumor characterized by various sites of metastasis, malignant transformation, and a high recurrence rate over time. Ameloblastic carcinoma(AC) is the term reserved for an ameloblastoma with histologic evidence of malignancy in the primary tumor. AC is classified into two types: most ACs occur de novo, and only few cases of malignant transformation of ameloblastoma become apparent. Here, we report a case of AC, arising from recurrent acanthomatous ameloblastoma on the maxillary sinus, in a 60-year-old male patient. The mass was first diagnosed as acanthomatous ameloblastoma; subsequently, surgical curettage was performed thrice while partial maxillectomy was performed twice. On the fifth recurrence, the tumor was identified as AC.

• 조극제(경북대학교 치과대학 구강악안면외과학 교실) | Keuk-Je Cho (Department of Oral & Maxillofacial Surgery School of Dentistry, Kyungpook National University)
• 김근환(경북대학교 치과대학 구강악안면외과학 교실) | Keun-Hwan Kim (Department of Oral & Maxillofacial Surgery School of Dentistry, Kyungpook National University)
• 김호준(경북대학교 치과대학 구강악안면외과학 교실) | Ho-Joon Kim (Department of Oral & Maxillofacial Surgery School of Dentistry, Kyungpook National University)
• 신홍인(경북대학교 치과대학 구강병리학 교실) | Hong-In Shin (Department of Oral Pathology School of Dentistry, Kyungpook National University)
• 권대근(경북대학교 치과대학 구강악안면외과학 교실) | Tae-Geon Kwon (Department of Oral & Maxillofacial Surgery School of Dentistry, Kyungpook National University)
• 최소영(경북대학교 치과대학 구강악안면외과학 교실) | So-Young Choi (Department of Oral & Maxillofacial Surgery School of Dentistry, Kyungpook National University) Correspondence