A case of multicentric carcinoma arising from 6 sites in the oral mucosa during 15 years

A case of oral multicentric carcinoma is reported. The patient was a 51-year-old man who presented with a tumorous nodule at the molar region of the left upper gingiva. The tumor was excised and diagnosed histologically to be verrucous carcinoma. Other tumorous lesions successively arose from the upper anterior gingiva, left buccal mucosa, lip mucosa, right upper gingiva, and right buccal mucosa during the next 15 years. Histopathological examination showed these tumors to be squamous cell carcinomas. They were all treated by local exision, and there has been no further reccurrence. Carcinogenesis caused by “field cancerization” or “field origin of tumors” of the oral mucosa was suggested in this patient.