We describe a case of CEOT of the mandible, which underwent malignant transformation and developed metastatic tumors of the lung after repeated local recurrence. The primary tumor revealed typical histological features of benign CEOT showing sheets of polyhedral epithelial cells associated with abundant eosinophilic amyloid-like materials. On the other hand, the locally recurrent tumors had malignant features, such as increased nuclear pleomorphism with frequent mitotic figures and vascular invasion of tumor cells, as well as increased proliferative activity assessed by immunostaining for Ki-67. Chemotherapy was carried out against the pulmonary metastatic lesions, which showed a drastic response after 3 courses of intravenous administration of cisplatin (CDDP). To date, a total of 6 courses of CDDP and 6 courses of nedaplatin (CDGP) have been done, and the remaining pulmonary tumors have been dormant. This suggests that platinum derivatives could be a chemotherapeutic agent of choice against this rare tumor.