Combined epithelial odontogenic tumors are very rare and represent hybrid lesion comprising adenomatoid odontogenic tumor intermixed with calcifying epithelial odontogenic tumor. The authors present 3 cases of combined epithelial odontogenic tumor which contained diagnostic areas for both adenomatoid odontogenic tumor and calcifying epithelial odontogenic tumor. Their behaviour and histogenesis were discussed.

Angiosarcoma is an extremely rare sarcoma arising from oral mucosa. We report a case of angiosarcoma in the right maxillary gingiva causing excessive bleeding. The lesion exhibited typical histologic features of angiosarcoma, showing infiltrative proliferation of polygonal endothelial cells and arborizing blood vessels. Tumor cells showed expression of CD 31 and factor VIII, but no expression of CD 34 antigen. The patient expired due to severe bleeding in the oral cavity.

Squamous cell carcinoma comprises about 95% of oral cancers. 까le gene디C 없mage in carcinogen-exposed fields is accumulated to transforrn norrnal mucosa in dysplas디c tissue and fmally invasive carcinoma through multistep process. This carcinogenic process has been a cause of the development of secondary tumors after the removal of primary carcmoma. πle improvement of therapeutic modalities of oral cancer has driven into the increase of multiple cancer occurrence in head and neck region. We experienced 3 pa디ents who had mul디ple squamous cell carcinomas in oral cavlty. π1ÎS study aimed to report multiple pr따laπ squamous cell carcinoma by clinical and pathologic examination and to discuss their molecular mechanism