Peripheral ameloblastic carcinoma (PAC) is a rare malignant neoplasm derived from either extraosseous remnants of the dental lamina or basal cells of the oral epithelium. PAC is defined as a type of extraosseous ameloblastoma with histologic evidence of malignant transformation of the epithelial component in both primary and metastatic lesions. PAC has the potential to invade the jaw bone and metastasize to regional lymph nodes or distant organs. This article reports an unusual case of PAC presenting initially as a polyp on the buccal gingiva of the right lower retromolar area of a 56-year-old edentulous male patient. The lesion was excised, and PAC was diagnosed. Because the wound healing was uneventful, the patient refused further wide excision. Three years later, the lesion recurred locally without underlying bone invasion but with multiple metastases to the lungs, bronchus, and pleura. Histologically, primary, recurrent, and metastatic tumors excised or biopsied showed typical features of PAC. Chemotherapy with cisplatin and epirubicin was given to the patient to control the recurrent and metastatic tumors, and it led to marked regression of the recurrent oral tumor and bilateral pulmonary carcinomatosis. However, chemotherapy was withheld because of anthracycline-related cardiomyopathy. The patient rapidly deteriorated and died of respiratory failure due to pneumonia and tumor progression 17 months after the diagnosis of recurrent PAC with lung metastasis. We suggest that wide surgical excision of the primary site is needed after a pathological diagnosis of PAC, and a patient with PAC requires meticulous follow-up. Because the undifferentiated tumor cells of PAC are sensitive to the two chemotherapeutic agents we gave this patient, combination chemotherapy may be the treatment of choice for recurrent and widespread PAC.